Submitted by brad on Sat, 2008-05-10 18:46.
It seems that half the programs I try and install under Windows want to have a “daemon” process with them, which is to say a portion of the program that is always running and which gets a little task-tray icon from which it can be controlled. Usually they want to also be run at boot time. In Windows parlance this is called a service.
There are too many of them, and they don’t all need to be there. Microsoft noticed this, and started having Windows detect if task tray icons were too static. If they are it hides them. This doesn’t work very well — they even hide their own icon for removing hardware, which of course is going to be static most of the time. And of course some programs now play games to make their icons appear non-static so they will stay visible. A pointless arms race.
All these daemons eat up memory, and some of them eat up CPU. They tend to slow the boot of the machine too. And usually not to do very much — mostly to wait for some event, like being clicked, or hardware being plugged in, or an OS/internet event. And the worst of them on their menu don’t even have a way to shut them down.
I would like to see the creation of a master deaemon/service program. This program would be running all the time, and it would provide a basic scripting language to perform daemon functions. Programs that just need a simple daemon, with a menu or waiting for events, would be strongly encouraged to prepare it in this scripting language, and install it through the master daemon. That way they take up a few kilobytes, not megabytes, and don’t take long to load. The scripting language should be able to react at least in a basic way to all the OS hooks, events and callbacks. It need not do much with them — mainly it would run a real module of the program that would have had a daemon. If the events are fast and furious and don’t pause, this program could stay resident and become a real daemon.
But having a stand alone program would be discouraged, certainly for boring purposes like checking for updates, overseeing other programs and waiting for events. The master program itself could get regular updates, as features are added to it as needed by would-be daemons.
Unix started with this philosophy. Most internet servers are started up by inetd, which listens on all the server ports you tell it, and fires up a server if somebody tries to connect. Only programs with very frequent requests, like E-mail and web serving, are supposed to keep something constantly running.
The problem is, every software package is convinced it’s the most important program on the system, and that the user mostly runs nothing but that program. So they act like they own the place. We need a way to only let them do that if they truly need it.
Submitted by brad on Fri, 2008-05-09 00:14.
I’m scanning my documents on an ADF document scanner now, and it’s largely pretty impressive, but I’m surprised at some things the system won’t do.
Double page feeding is the bane of document scanning. To prevent it, many scanners offer methods of double feed detection, including ultrasonic detection of double thickness and detection when one page is suddenly longer than all the others (because it’s really two.)
There are a number of other tricks they could do, I think. I think a paper feeder that used air suction or gecko-foot van-der-waals force pluckers on both sides of a page to try to pull the sides in two different directions could help not just detect, but eliminate such feeds.
However, the most the double feed detectors do is signal an exception to stop the scan. Which means work re-feeding and a need to stand by.
However, many documents have page numbers. And we’re going to OCR them and the OCR engine is pretty good at detecting page numbers (mostly out of desire to remove them.) However, it seems to me a good approach would be to look for gaps in the page numbers, especially combined with the other results of a double feed. Then don’t stop the scan, just keep going, and report to the operator which pages need to be scanned again. Those would be scanned, their number extracted, and they would be inserted in the right place in the final document.
Of course, it’s not perfect. Sometimes page numbers are not put on blank pages, and some documents number only within chapters. So you might not catch everything, but you could catch a lot of stuff. Operators could quickly discern the page numbering scheme (though I think the OCR could do this too) to guide the effort.
I’m seeking a maximum convenience workflow. I think to do that the best plan is to have several scanners going, and the OCR after the fact in the background. That way there’s always something for the operator to do — fixing bad feeds, loading new documents, naming them — for maximum throughput. Though I also would hope the OCR software could do better at naming the documents for you, or at least suggesting names. Perhaps it can, the manual for Omnipage is pretty sparse.
While some higher end scanners do have the scanner figure out the size of the page (at least the length) I am not sure why it isn’t a trivial feature for all ADF scanners to do this. My $100 Strobe sheetfed scanner does it. That my $6,000 (retail) FI-5650 needs extra software seems odd to me.
Submitted by brad on Tue, 2008-05-06 16:25.
PCs can go into standby mode (just enough power to preserve the RAM and do wake-on-lan) and into hibernate mode (where they write out the RAM to disk, shut down entirely and restore from disk later) as well as fully shut down.
Standby mode comes back up very fast, and should be routinely used on desktops. In fact, non-server PCs should consider doing it as a sort of screen saver since the restart can be so quick. It’s also popular on laptops but does drain the battery in a few days keeping the RAM alive. Many laptops will wake up briefly to hibernate if left in standby so long that the battery gets low, which is good.
How about this option: Write the ram contents out to disk, but also keep the ram alive. When the user wants to restart, they can restart instantly, unless something happened to the ram. If there was a power flicker or other trouble, notice the ram is bad and restart from disk. Usually you don’t care too much about the extra time needed to write out to disk when suspending, other than for psychological reasons where you want to be really sure the computer is off before leaving it. It’s when you come back to the computer that you want instant-on.
In fact, since RAM doesn’t actually fail all that quickly, you might even find you can restore from RAM after a brief power flicker. In that case, you would want to store a checksum for all blocks of RAM, and restore any from disk that don’t match the checksum.
To go further, one could also hibernate to newer generations of fast flash memory. Flash memory is getting quite cheap, and while older generations aren’t that quick, they seek instantaneously. This allows you to reboot a machine with its memory “paged out” to flash, and swap in pages at random as they are needed. This would allow a special sort of hybrid restore:
- Predict in advance which pages are highly used, and which are enough to get the most basic functions of the OS up. Write them out to a special contiguous block of hibernation disk. Then write out the rest, to disk and flash.
- When turning on again, read this block of contiguous disk and go “live.” Any pages needed can then be paged in from the flash memory as needed, or if the flash wasn’t big enough, unlikely pages can come from disk.
- In the background, restore the rest of the pages from the faster disk. Eventually you are fully back to ram.
This would allow users to get a fairly fast restore, even from full-off hibernation. If they click on a rarely used program that was in ram, it might be slow as stuff pages in, but still not as bad as waiting for the whole restore.
Submitted by brad on Thu, 2008-02-21 12:44.
A big trend in systems operation these days is the use of virtual machines — software systems which emulate a standalone machine so you can run a guest operating system as a program on top of another (host) OS. This has become particularly popular for companies selling web hosting. They take one fast machine and run many VMs on it, so that each customer has the illusion of a standalone machine, on which they can do anything. It’s also used for security testing and honeypots.
The virtual hosting is great. Typical web activity is “bursty.” You would like to run at a low level most of the time, but occasionally burst to higher capacity. A good VM environment will do that well. A dedicated machine has you pay for full capacity all the time when you only need it rarely. Cloud computing goes beyond this.
However, the main limit to a virtual machine’s capacity is memory. Virtual host vendors price their machines mostly on how much RAM they get. And a virtual host with twice the RAM often costs twice as much. This is all based on the machine’s physical ram. A typical vendor might take a machine with 4gb, keep 256mb for the host and then sell 15 virtual machines with 256mb of ram. They will also let you “burst” your ram, either into spare capacity or into what the other customers are not using at the time, but if you do this for too long they will just randomly kill processes on your machine, so you don’t want to depend on this.
The problem is when they give you 256MB of ram, that’s what you get. A dedicated linux server with 256mb of ram will actually run fairly well, because it uses paging to disk. The server loads many programs, but a lot of the memory used for these programs (particularly the code) is used rarely, if ever, and swaps out to disk. So your 256mb holds the most important pages of ram. If you have more than 256mb of important, regularly used ram, you’ll thrash (but not die) and know you need to buy more.
The virtual machines, however, don’t give you swap space. Everything stays in ram. And the host doesn’t swap it either, because that would not be fair. If one VM were regularly swapping to disk, this would slow the whole system down for everybody. One could build a fair allocation for that but I have not heard of it.
In addition, another big memory saving is lost — shared memory. In a typical system, when two processes use the same shared library or same program, this is loaded into memory only once. It’s read-only so you don’t need to have two copies. But on a big virtual machine, we have 15 copies of all the standard stuff — 15 kernels, 15 MYSQL servers, 15 web servers, 15 of just about everything. It’s very wasteful.
So I wonder if it might be possible to do one of the following:
- Design the VM so that all binaries and shared libraries can be mounted from a special read-only filesystem which is actually on the host. This would be an overlay filesystem so that individual virtual machines could change it if need be. The guest kernel, however, would be able to load pages from these files, and they would be shared with any other virtual machine loading the same file.
- Write a daemon that regularly uses spare CPU to scan the pages of each virtual machine, hashing them. When two pages turn out to be identical, release one and have both VMs use the common copy. Mark it so that if one writes to it, a duplicate is created again. When new programs start it would take extra RAM, but within a few minutes the memory would be shared.
These techniques require either a very clever virtualizer or modified guests, but their savings are so worthwhile that everybody would want to do it this way on any highly loaded virtual machine. Of course, that goes against the concept of “run anything you like” and makes it “run what you like, but certain standard systems are much cheaper.”
This, and allowing some form of fair swapping, could cause a serious increase in the performance and cost of VMs.
Submitted by brad on Tue, 2008-02-19 21:11.
If you have read my articles on power you know I yearn for the days when we get smart power so we have have universal supplies that power everything. This hit home when we got a new Thinkpad Z61 model, which uses a new power adapter which provides 20 volts at 4.5 amps and uses a new, quite rare power tip which is 8mm in diameter. For almost a decade, thinkpads used 16.5 volts and used a fairly standard 5.5mm plug. It go so that some companies standardized on Thinkpads and put cheap 16 volt TP power supplies in all the conference rooms, allowing employees to just bring their laptops in with no hassle.
Lenovo pissed off their customers with this move. I have perhaps 5 older power supplies, including one each at two desks, one that stays in the laptop bag for travel, one downstairs and one running an older ThinkPad. They are no good to me on the new computer.
Lenovo says they knew this would annoy people, and did it because they needed more power in their laptops, but could not increase the current in the older plug. I’m not quite sure why they need more power — the newer processors are actually lower wattage — but they did.
Here’s something they could have done to make it better. read more »
Submitted by brad on Sat, 2008-01-12 16:33.
I’ve written before about both the desire for universal dc power and more simply universal laptop power at meeting room desks.
Today I want to report we’re getting a lot closer. A new generation of cheap “buck and boost” ICs which can handle more serious wattages with good efficiency has come to the market. This means cheap DC to DC conversion, both increasing and decreasing voltages. More and more equipment is now able to take a serious range of input voltages, and also to generate them. Being able to use any voltage is important for battery powered devices, since batteries start out with a high voltage (higher than the one they are rated for) and drop over their time to around 2/3s of that before they are viewed as depleted. (With some batteries, heavy depletion can really hurt their life. Some are more able to handle it.)
With a simple buck converter chip, at a cost of about 10-15% of the energy, you get a constant voltage out to matter what the battery is putting out. This means more reliable power and also the ability to use the full capacity of the battery, if you need it and it won’t cause too much damage. These same chips are in universal laptop supplies. Most of these supplies use special magic tips which fit the device they are powering and also tell the supply what voltage and current it needs. read more »
Submitted by brad on Tue, 2007-11-13 13:20.
Ok, I haven't had a new laptop in a while so perhaps this already happens, but I'm now carrying more devices that can charge off the USB power, including my cell phone. It's only 2.5 watts, but it's good enough for many purposes.
However, my laptops, and desktops, do not provide USB power when in standby or off. So how about a physical or soft switch to enable that? Or even a smart mode in the US that lets you list what devices you want to keep powered and which ones you don't? (This would probably keep all devices powered if any one such device is connected, unless you had individual power control for each plug.)
This would only be when on AC power of course, not on battery unless explicitly asked for as an emergency need.
To get really smart a protocol could be developed where the computer can ask the USB device if it needs power. A fully charged device that plans to sleep would say no. A device needing charge could say yes.
Of course, you only want to do this if the power supply can efficiently generate 5 volts. Some PC power supplies are not efficient at low loads and so may not be a good choice for this, and smaller power supplies should be used.
Submitted by brad on Tue, 2007-07-10 00:42.
For much of history, we’ve used removable media for backup. We’ve used tapes of various types, floppy disks, disk cartridges, and burnable optical disks. We take the removable media and keep a copy offsite if we’re good, but otherwise they sit for a few decades until they can’t be read, either because they degraded or we can’t find a reader for the medium any more.
But I now declare this era over. Disk drives are so cheap — 25 cents/gb and falling, that it no longer makes sense to do backups to anything but hard disks. We may use external USB drives that are removable, but at this point our backups are not offline, they are online. Thanks to the internet, I even do offsite backup to live storage. I sync up over the internet at night, and if I get too many changes (like after an OS install, or a new crop of photos) I write the changes to a removable hard disk and carry it over to the offsite hard disk.
Of course, these hard drives will fail, perhaps even faster than CD-roms or floppies. But the key factor is that the storage is online rather than offline, and each new disk is 2 to 3 times larger than the one it replaced. What this means is that as we change out our disks, we just copy our old online archives to our new online disk. By constantly moving the data to newer and newer media — and storing it redundantly with online, offsite backup, the data are protected from the death that removable media eventually suffer. So long as disks keep getting bigger and cheaper, we won’t lose anything, except by beng lazy. And soon, our systems will get more automated at this, so it’s hard to set up a computer that isn’t backed up online and remotely. We may still lose things because we lose encryption keys, but it won’t be for media.
Thus, oddly, the period of the latter part of the 20th century will be a sort of “dark ages” to future data archaeologists. Those disks will be lost. The media may be around, but you will have to do a lot of work to recover them — manual work. However, data from the early 21st onward will be there unless it was actively deleted or encrypted.
Of course this has good and bad consequences. Good for historians. Perhaps not so good for privacy.
Submitted by brad on Tue, 2007-07-03 15:15.
Hotels are now commonly sporting flat widescreen TVs, usually LCD HDTVs at the 720p resolution, which is 1280 x 720 or similar. Some of these TVs have VGA ports or HDMI (DVI) ports, or they have HDTV analog component video (which is found on some laptops but not too many.) While 720p resolution is not as good as the screens on many laptops, it makes a world of difference on a PDA. As our phone/PDA devices become more like the iPhone, it would be very interesting to see hotels guarantee that their room offers the combination of:
- A bluetooth keyboard (with USB and mini-USB as a backup)
- A similar optical mouse
- A means to get video into the HDTV
- Of course, wireless internet
- Our dreamed of universal DC power jack (or possibly inductive charging.)
Tiny devices like the iPhone won’t sport VGA or even component video out 7 pin connectors, though they might do HDMI. It’s also not out of the question to go a step further and do a remote screen protocol like VNC over the wireless ethernet or bluetooth.
This would engender a world where you carry a tiny device like the iPhone, which is all touchscreen for when you are using it in the mobile environment. However, when you sit down in your hotel room (or a few other places) you could use it like a full computer with a full screen and keyboard. (There are also quite compact real-key bluetooth keyboards and mice which travelers could also bring. Indeed, since the iPhone depends on a multitouch interface, an ordinary mouse might not be enough for it, but you could always use its screen for such pointing, effectively using the device as the touchpad.)
Such stations need not simply be in hotels. Smaller displays (which are now quite cheap) could also be present at workstations on conference tables or meeting rooms, or even for rent in public. Of course rental PCs in public are very common at internet cafes and airport kiosks, but using our own device is more tuned to our needs and more secure (though using a rented keyboard presents security risks.)
One could even imagine stations like these randomly scattered around cities behind walls. Many retailers today are putting HDTV flat panels in their windows instead of signs, and this will become a more popular trend. Imagine being able to borrow (for free or for a rental fee) such screens for a short time to do a serious round of web surfing on your portable device with high resolution, and local wifi bandwidth. Such a screen could not provide you with a keyboard or mouse easily, but the surfing experience would be much better than the typical mobile device surfing experience, even the iPhone model of seeing a blurry, full-size web page and using multitouch to zoom in on the relevant parts. Using a protocol like vnc could provide a good surfing experience for pedestrians.
Cars are also more commonly becoming equipped with screens, and they are another place we like to do mobile surfing. While the car’s computer should let you surf directly, there is merit in being able to use that screen as a temporary large screen for one’s mobile device.
Until we either get really good VR glasses or bright tiny projectors, screen size is going to be an issue in mobile devices. A world full of larger screens that can be grabbed for a few minutes use may be a good answer.
Submitted by brad on Fri, 2007-06-08 14:43.
For many of us, E-mail has become our most fundamental tool. It is not just the way we communicate with friends and colleagues, it is the way that a large chunk of the tasks on our “to do” lists and calendars arrive. Of course, many E-mail programs like Outlook come integrated with a calendar program and a to-do list, but the integration is marginal at best. (Integration with the contact manager/address book is usually the top priority.)
If you’re like me you have a nasty habit. You leave messages in your inbox that you need to deal with if you can’t resolve them with a quick reply when you read them. And then those messages often drift down in the box, off the first screen. As a result, they are dealt with much later or not at all. With luck the person mails you again to remind you of the pending task.
There are many time management systems and philosophies out there, of course. A common theme is to manage your to-do list and calendar well, and to understand what you will do and not do, and when you will do it if not right away.
I think it’s time to integrate our time management concepts with our E-mail. To realize that a large number of emails or threads are also a task, and should be bound together with the time manager’s concept of a task.
For example, one way to “file” an E-mail would be to the calendar or a day oriented to-do list. You might take an E-mail and say, “I need 20 minutes to do this by Friday” or “I’ll do this after my meeting with the boss tomorrow.” The task would be tied to the E-mail. Most often, the tasks would not be tied to a specific time the way calendar entries are, but would just be given a rough block of time within a rough window of hours or days.
It would be useful to add these “when to do it” attributes to E-mails, because now delegating a task to somebody else can be as simple as forwarding the E-mail-message-as-task to them.
In fact, because, as I have noted, I like calendars with free-form input (ie. saying “Lunch with Peter 1pm tomorrow” and having the calender understand exactly what to do with it) it makes sense to consider the E-mail window as a primary means of input to the calendar. For example, one might add calendar entries by emailing them to a special address that is processed by the calendar. (That’s a useful idea for any calendar, even one not tied at all to the E-mail program.)
One should also be able to assign tasks to places (a concept from the “Getting Things Done” book I have had recommended to me.) In this case, items that will be done when one is shopping, or going out to a specific meeting, could be synced or sent appropriately to one’s mobile device, but all with the E-mail metaphor.
Because there are different philosophies of time management, all with their fans, one monolithic e-mail/time/calendar/todo program may not be the perfect answer. A plug-in architecture that lets time managers integrate nicely with E-mail could be a better way to do it.
Some of these concepts apply to the shared calendar concepts I wrote about last month.
Submitted by brad on Mon, 2007-06-04 11:01.
Here’s a new approach to linux adoption. Create a linux distro which converts a Windows machine to linux, marketed as a way to solve many of your virus/malware/phishing woes.
Yes, for a long time linux distros have installed themselves on top of a windows machine dual-boot. And there are distros that can run in a VM on windows, or look windows like, but here’s a set of steps to go much further, thanks to how cheap disk space is today. read more »
- Yes, the distro keeps the Windows install around dual boot, but it also builds a virtual machine so it can be run under linux. Of course hardware drivers differ when running under a VM, so this is non-trivial, and Windows XP and later will claim they are stolen if they wake up in different hardware. You may have to call Microsoft, which they may eventually try to stop.
- Look through the Windows copy and see what apps are installed. For apps that migrate well to linux, either because they have equivalents or run at silver or gold level under Wine, move them into linux. Extract their settings and files and move those into the linux environment. Of course this is easiest to do when you have something like Firefox as the browser, but IE settings and bookmarks can also be imported.
- Examine the windows registry for other OS settings, desktop behaviours etc. Import them into a windows-like linux desktop. Ideally when it boots up, the user will see it looking and feeling a lot like their windows environment.
- Using remote window protocols, it’s possible to run windows programs in a virtual machine with their window on the X desktop. Try this for some apps, though understand some things like inter-program communication may not do as well.
- Next, offer programs directly in the virtual machine as another desktop. Put the windows programs on the windows-like “start” menu, but have them fire up the program in the virtual machine, or possibly even fire up the VM as needed. Again, memory is getting very cheap.
- Strongly encourage the Windows VM be operated in a checkpointing manner, where it is regularly reverted to a base state, if this is possible.
- The linux box, sitting outside the windows VM, can examine its TCP traffic to check for possible infections or strange traffic to unusual sites. A database like the siteadvisor one can help spot these unusual things, and encourage restoring the windows box back to a safe checkpoint.
Submitted by brad on Sun, 2007-04-15 16:45.
The use of virtual machines is getting very popular in the web hosting world. Particularly exciting to many people is Amazon.com’s EC2 — which means Elastic Compute Cloud. It’s a large pool of virtual machines that you can rent by the hour. I know people planning on basing whole companies on this system, because they can build an application that scales up by adding more virtual machines on demand. It’s decently priced and a lot cheaper than building it yourself in most cases.
In many ways, something like EC2 would be great for all those web sites which deal with the “slashdot” effect. I hope to see web hosters, servers and web applications just naturally allow scaling through the addition of extra machines. This typically means either some round-robin-DNS, or a master server that does redirects to a pool of servers, or a master cache that processes the data from a pool of servers, or a few other methods. Dealing with persistent state that can’t be kept in cookies requires a shared database among all the servers, which may make the database the limiting factor. Rumours suggest Amazon will release an SQL interface to their internal storage system which presumably is highly scalable, solving that problem.
As noted, this would be great for small to medium web sites. They can mostly run on a single server, but if they ever see a giant burst of traffic, for example by being linked to from a highly popular site, they can in minutes bring up extra servers to share the load. I’ve suggested this approach for the Battlestar Galactica Wiki I’ve been using — normally their load is modest, but while the show is on, each week, predictably, they get such a huge load of traffic when the show actually airs that they have to lock the wiki down. They have tried to solve this the old fashioned way — buying bigger servers — but that’s a waste when they really just need one day a week, 22 weeks a year, of high capacity.
However, I digress. What I really want to talk about is using such systems to get access to all sorts of platforms. As I’ve noted before, linux is a huge mishmash of platforms. There are many revisions of Ubuntu, Fedora, SuSE, Debian, Gentoo and many others out there. Not just the current release, but all the past releases, in both stable, testing and unstable branches. On top of that there are many versions of the BSD variants. read more »
Submitted by brad on Sun, 2007-03-04 19:50.
Most of us, when we travel, put appointments we will have while on the road into our calendars. And we usually enter them in local time. ie. if I have a 1pm appointment in New York, I set it for 1pm not 10am in my Pacific home time zone. While some calendar programs let you specify the time zone for an event, most people don't, and many people also don't change the time zone when they cross a border, at least not right away. (I presume that some cell phone PDAs pick up the new time from the cell network and import it into the PDA, if the network provides that.) Many PDAs don't really even let you set the time zone, just the time.
Here's an idea that's simple for the user. Most people put their flights into their calendars. In fact, most of the airline web sites now let you download your flight details right into your calendar. Those flight details include flight times and the airport codes.
So the calendar software should notice the flight, look up the destination airport code, and trigger a time zone change during the flight. This would also let the flight duration look correct in the calendar view window, though it would mean some "days" would be longer than others, and hours would repeat or be missing in the display.
You could also manually enter magic entries like "TZ to PST" or similar which the calendar could understand as a command to change the zone at that time.
Of course, I could go on many long rants about the things lacking from current calendar software, and perhaps at some point I will, but this one struck me as interesting because, in the downloaded case, the UI for the user is close to invisible, and I always like that.
It becomes important when we start importing our "presence" from our calendar, or get alerts from our devices about events, we don't want these things to trigger in the wrong time zone.
Submitted by brad on Mon, 2007-01-22 15:02.
Radio technology has advanced greatly in the last several years, and will advance more. When the FCC opened up the small “useless” band where microwave ovens operate to unlicenced use, it generated the greatest period of innovation in the history of radio. As my friend David Reed often points out, radio waves don’t interfere with one another out in the ether. Interference only happens at a receiver, usually due to bad design. I’m going to steal several of David’s ideas here and agree with him that a powerful agency founded on the idea that we absolutely must prevent interference is a bad idea.
My overly simple summary of a replacement regime is just this, “Don’t be selfish.” More broadly, this means, “don’t use more spectrum than you need,” both at the transmitting and receiving end. I think we could replace the FCC with a court that adjudicates problems of alleged interference. This special court would decide which party was being more selfish, and tell them to mend their ways. Unlike past regimes, the part 15 lesson suggests that sometimes it is the receiver who is being more spectrum selfish.
Here are some examples of using more spectrum than you need:
- Using radio when you could have readily used wires, particularly the internet. This includes mixed mode operations where you need radio at the endpoints, but could have used it just to reach wired nodes that did the long haul over wires.
- Using any more power than you need to reliably reach your receiver. Endpoints should talk back if they can, over wires or radio, so you know how much power you need to reach them.
- Using an omni antenna when you could have used a directional one.
- Using the wrong band — for example using a band that bounces and goes long distance when you had only short-distance, line of sight needs.
- Using old technology — for example not frequency hopping to share spectrum when you could have.
- Not being dynamic — if two transmitters who can’t otherwise avoid interfering exist, they should figure out how one of them will fairly switch to a different frequency (if hopping isn’t enough.)
As noted, some of these rules apply to the receiver, not just the transmitter. If a receiver uses an omni antenna when they could be directional, they will lose a claim of interference unless the transmitter is also being very selfish. If a receiver isn’t smart enough to frequency hop, or tell its transmitter what band or power to use, it could lose.
Since some noise is expected not just from smart transmitters, but from the real world and its ancient devices (microwave ovens included) receivers should be expected to tolerate a little interference. If they’re hypersensitive to interference and don’t have a good reason for it, it’s their fault, not necessarily the source’s. read more »
Submitted by brad on Thu, 2007-01-04 14:21.
A recent Forbes items pointed to my earlier posts on eBay Feedback so I thought it was time to update them. Note also the eBay tag for all posts on eBay including comments on the new non-feedback rules.
I originally mused about blinding feedback or detecting revenge feedback. It occurs to me there is a far, far simpler solution. If the first party leaves negative feedback, the other party can’t leave feedback at all. Instead, the negative feedback is displayed both in the target’s feedback profile and also in the commenter’s profile as a “negative feedback left.” (I don’t just mean how you can see it in the ‘feedback left for others’ display. I mean it would show up in your own feedback that you left negative feedback on a transaction as a buyer or seller. It would not count in your feedback percentage, but it would display in the list a count of negatives you left, and the text response to the negative made by the other party if any.)
Why? Well, once the first feedbacker leaves a negative, how much information is there, really, in the response feedback? It’s a pretty rare person who, having been given a negative feedback is going to respond with a positive! Far more likely they will not leave any feedback at all if they admit the problem was their fault. Or that they will leave revenge. So if there’s no information, it’s best to leave it out of the equation.
This means you can leave negatives without fear of revenge, but it will be clearly shown to people who look at your profile whether you leave a lot of negatives or not, and they can judge from comments if you are spiteful or really had some problems. This will discourage some negative feedback, since people will not want a more visible reputation of giving lots of negatives. A typical seller will expect to have given a bunch of negatives to deadbeat buyers who didn’t pay, and the comments will show that clearly. If, however, they have an above average number of disputes over little things, that might scare customers off — and perhaps deservedly.
I don’t know if eBay will do this so I’ve been musing that it might be time for somebody to make an independent reputation database for eBay, and tie it in with a plugin like ShortShip. This database could spot revenge feedbacks, note the order of feedbacks, and allow more detailed commentary. Of course if eBay tries to stop it, it has to be a piece of software that does all the eBay fetching from user’s machines rather then a central server.
Submitted by brad on Sat, 2006-12-30 13:29.
I’ve thought digital picture frames were a nice idea for a while, but have not yet bought one. The early generation were vastly overpriced, and the current cheaper generation still typically only offer 640x480 resolution. I spend a lot to produce quality, high-res photography, and while even a megapixel frame would be showing only a small part of my available resolution, 1/4 megapixel is just ridiculous.
I’ve written before that I think a great product would either be flat panels that come with or can use a module to provide 802.11 and a simple protocol for remote computers to display stuff on them. Or I have wished for a simple and cheap internet appliance that would feature 802.11 and a VGA output to do the job. 1280x1024 flat panels now sell for under $150, and it would not take much in the way of added electronics to turn them into an 802.11 or even USB-stick/flashcard based digital photo frame with 4 times the resolution of the similarly priced dedicated frames.
One answer many people have tried is to convert an old laptop to a digital photo frame. 800x600 laptops are dirt cheap, and in fact I have some that are too slow to use for much else. 1024x768 laptops can also be had for very low prices on ebay, especially if you will take a “broken” one that’s not broken when it comes to being a frame — for example if it’s missing the hard disk, or the screen hinges (but not the screen) are broken. A web search will find you several tutorials on converting a laptop.
To make it really easy, what would be great is a ready to go small linux distribution aimed at this purpose. Insert a CD or flash card with the distribution on it and be ready to go as a picture frame.
Ideally, this distro would be set to run without a hard disk. You don’t want to spin the hard disk since that makes noise and generates heat. Some laptops won’t boot from USB or flash, so you might need a working hard drive to get booted, but ideally you would unmount it and spin it down after booting.
Having a flash drive is possible with just about all laptops, because PCMCIA compact flash adapters can be had for under $10. Laptops with USB can use cheaply available thumb-drives. PCMCIA USB adapters are also about $10, but beware that really old laptops won’t take the newer-generation “cardbus” models.
While some people like to put pictures into the frame using a flash card or stick, and this can be useful, I think the ideal way to do it is to use 802.11. And this is for the grandmother market. One of the interesting early digital picture frames had a phone plug on it. The frame would dial out by modem to download new pictures that you uploaded to the vendor’s site. The result was that grandma could see new pictures on a regular basis without doing anything. The downside was this meant an annoying monthly fee to cover the modem costs.
But today 802.11 is getting very common. Indeed, even if grandma is completely internet-phobic, there’s probably a neighbour’s 802.11 visible in her house, and what neighbour would not be willing to give permission for a function such as this. Then the box can be programmed to download and display photos from any typical photo web site, and family members can quickly upload or email photos to that web site.
Of course if there is no 802.11 then flash is the way to do it. USB sticks are ideal as they are cheap and easy to insert and remove, even for the computer-phobic. I doubt you really want to just stick a card out of a camera, people want to prepare their slideshows. (In particular, you want to pre-scale the images down to screen size for quick display and to get many more in the memory.) 800x600 pictures are in fact so small — 50kb can be enough — that you could even build the frame with no flash, just an all-ram linux that loads from flash, CD or spun-down hard drive, and keeps a 100 photos in spare ram, and sucks down new ones over the network as needed. This mode eliminates the need for worrying about drivers for flash or USB. The linux would run in frame-buffer mode, there would be no X server needed.
The key factor is that the gift giver prepares the box and mounts it on the wall, plugged in. After that the recipient need do nothing but look at it, while new photos arrive from time to time. While remote controls are nice (and can be done on the many laptops that feature infrared sensors) the zero-user-interface (ZUI) approach does wonders with certain markets.
Update: I’ve noticed that adapters for Laptop mini-IDE to compact flash are under $10. So you can take any laptop that’s missing a drive and insert a flash card as the drive, with no worries about whether you can boot from a removable device. You might still want an external flash card slot if it’s not going to be wifi, but you can get a silent computer easily and cheaply this way. (Flash disk is slower than HDD to read by has no seek time.)
Even for the builder the task could be very simple.
- Unscrew or break the hinges to fold the screen against the bottom of the laptop (with possible spacer for heat)
- Install, if needed, 802.11 card, USB card or flash slot and flash — or flash IDE.
- Install linux distro onto hard disk, CD or flash
- Configure by listing web URL where new photo information will be found, plus URL for parameters such as speed of slideshow, fade modes etc.
- Configure 802.11 parameters
- Put it in a deep picture frame
- Set bios to auto turn-on after power failure if possible
- Mount on wall or table and plug in.
Submitted by brad on Mon, 2006-12-18 02:57.
I’ve been writing recently about the linux upgrade nightmares that continue to trouble the world. The next in my series of ideas is a suggestion that we try to measure how well upgrades go, and make a database of results available.
Millions of people are upgrading packages every day. And it usually goes smoothly. However, when it doesn’t, it would be nice if that were recorded and shared. Over time, one could develop an idea of which upgrades are safer than others. Thus, when it’s time to upgrade many packages, the system could know which ones always go well, and which ones might deserve a warning, or should only be done if you don’t have something critical coming up that day.
We already know some of these. Major packages like Apache are often a chore, though they’ve done a lot more by using a philosophy of configuration files I heartily approve of — dividing up configuration to put config by different people in different files.
Some detection is automated. For example, the package tools detect if a configuration file is being upgraded after it’s been changed and offer the user a chance to keep the new one, their old one, or hand-mix them. What choice the user makes could be noted to measure how well the upgrades go. Frankly, any upgrade that even presents the user with questions should get some minor points against it, but if a user has to do a hand merge it should get lots of negative points.
Upgrades that got no complaint should be recorded, and upgrades that get an explicit positive comment (ie. the user actively says it went great) should also be noted. Of course, any time a user does an explicit negative comment that’s the most useful info of all. Users should be able to browse a nice GUI of all their recent upgrades — even months later — and make notes on how well things are going. If you discover something broken, it should be easy to make the report.
Then, when it comes time to do a big upgrade, such as a distribution upgrade, certain of the upgrades can be branded as very, very safe, and others as more risky. In fact, users could elect to just do only the safe ones. Or they could even elect to automatically do safe upgrades, particularly if there are lots of safety reports on their exact conditions (former and current version, dependencies in place.) Automatic upgrading is normally a risky thing, it can generate the risk of a problem accidentally spreading like wildfire, but once you have lots of reports about how safe it is, you can make it more and more automatic.
Thus the process might start with upgrading the 80% of packages that are safe, and then the 15% that are mostly safe. Then allocate some time and get ready for the ones that probably will involve some risk or work. Of course, if everything depends on a risky change (such as a new libc) you can’t get that order, but you can still improve things.
There is a risk of people gaming the database, though in non-commercial environments that is hopefully small. It may be necessary to have reporters use IDs that get reputations. For privacy reasons, however, you want to anonymize data after verifying it.
Submitted by brad on Sat, 2006-12-16 03:15.
I’ve spoken before about ZUI (Zero User Interface) and how often it’s the right interface.
One important system that often has too complex a UI is backup. Because of that, backups
often don’t get done. In particular offsite backups, which are the only way to deal with
fire and similar catastrophe.
Here’s a rough design for a ZUI offsite backup. The only UI at a basic level is just
installing and enabling it — and choosing a good password (that’s not quite zero UI but
it’s pretty limited.)
Once enabled, the backup system will query a central server to start looking for backup
buddies. It will be particularly interested in buddies on your same LAN (though it will
not consider them offsite.) It will also look for buddies on the same ISP or otherwise close
by, network-topology wise. For potential buddies, it will introduce the two of you and let
you do bandwidth tests to measure your bandwidth.
At night, the tool would wait for your machine and network to go quiet, and likewise the
buddy’s machines. It would then do incremental backups over the network. These would
be encrypted with secure keys. Those secure keys would in turn be stored on your own
machine (in the clear) and on a central server (encrypted by your password.)
The backup would be clever. It would identify files on your system which are common
around the network — ie. files of the OS and installed software packages — and know it
doesn’t have to back them up directly, it just has to record their presence and the
fact that they exist in many places. It only has to transfer your own created files.
Your backups are sent to two or more different buddies each, compressed. Regular checks
are done to see if the buddy is still around. If a buddy leaves the net, it quickly
will find other buddies to store data on. Alas, some files, like video, images and
music are already compressed, so this means twice as much storage is needed for backup
as the files took — though only for your own generated files. So you do have to
have a very big disk 3 times bigger than you need, because you must store data for
the buddies just as they are storing for you. But disk is getting very cheap.
(Another alternative is RAID-5 style. In RAID-5 style, you distribute each
file to 3 or more buddies, except in the RAID-5 parity system, so that any
one buddy can vanish and you can still recover the file. This means you
may be able to get away with much less excess disk space. There are also
redundant storage algorithms that let you tolerate the loss of 2 or even 3
of a larger pool of storers, at a much more modest cost than using double
All this is, as noted, automatic. You don’t have to do anything to make it happen,
and if it’s good at spotting quiet times on the system and network, you don’t even
notice it’s happening, except a lot more of your disk is used up storing data for
It is the automated nature that is so important. There have been other proposals
along these lines, such as MNET and some commercial network backup apps, but never an app you
just install, do quick setup and then forget about until you need to restore a
file. Only such an app will truly get used and work for the user.
Restore of individual files (if your system is still alive) is easy. You have
the keys on file, and can pull your file from the buddies and decrypt it with
Loss of a local disk is more work, but if you have multiple computers in
the household, the keys could be stored on other computers on the same
LAN (alas this does require UI to approve this) and then you can go to
another computer to get the keys to rebuild the lost disk. Indeed, using
local computers as buddies is a good idea due to speed, but they don’t
provide offsite backup. It would make sense for the system, at the cost of
more disk space, to do both same-LAN backup and offsite. Same-LAN for
hardware failures, offsite for building-burns-down failures.
In the event of a building-burns-down failure, you would have to go
to the central server, and decrypt your keys with that password. Then you can get your
keys and find your buddies and restore your files. Restore would not
be ZUI, because we need no motiviation to do restore. It is doing regular
backups we lack motivation for.
Of course, many people have huge files on disk. This is particularly true
if you do things like record video with MythTV or make giant photographs,
as I do. This may be too large for backup over the internet.
In this case, the right thing to do is to backup the smaller files first,
and have some UI. This UI would warn the user about this, and suggest
options. One option is to not back up things like recorded video. Another
is to rely only on local backup if it’s available. Finally, the system
should offer a manual backup of the large files, where you connect a
removable disk (USB disk for example) and transfer the largest files to
it. It is up to you to take that offsite on a regular basis if you can.
However, while this has a UI and physical tasks to do, if you don’t do
it it’s not the end of the world. Indeed, your large files may get
backed up, slowly, if there’s enough bandwidth.
Submitted by brad on Fri, 2006-08-11 17:06.
Everybody’s pulling out IBM PC stories on the 25th anniversary so I thought I would relate mine. I had been an active developer as a teen for the 6502 world — Commodore Pet, Apple ][, Atari 800 and the like, and sold my first game to Personal Software Inc. back in 1979. PSI was just starting out, but the founders hired me on as their first employee to do more programming. The company became famous shortly thereafter by publishing VisiCalc, which was the first serious PC application, and the program that helped make Apple as a computer company outside the hobby market.
In 1981, I came back for a summer job from school. Mitch Kapor, who had worked for Personal Software in 1980 (and had been my manager at the time) had written a companion for VisiCalc, called VisiPlot. VisiPlot did graphs and charts, and a module in it (VisiTrend) did statistical analysis. Mitch had since left, and was on his way to founding Lotus. Mitch had written VisiPlot in Apple ][ Basic, and he won’t mind if I say it wasn’t a masterwork of code readability, and indeed I never gave it more than a glance. Personal Software, soon to be renamed VisiCorp, asked me to write VisiPlot from scratch, in C, for an un-named soon to be released computer.
I didn’t mention this, but I had never coded in C before. I picked up a copy of the Kernighan and Ritchie C manual, and read it as my girlfriend drove us over the plains on my trip from Toronto to California.
I wasn’t told much about the computer I would be coding for. Instead, I defined an API for doing I/O and graphics, and wrote to a generalized machine. Bizarrely (for 1981) I did all this by dialing up by modem to a unix computer time sharing service called CCA on the east coast. I wrote and compiled in C on unix, and defined a serial protocol to send graphics back to, IIRC an Apple computer acting as a terminal. And, in 3 months, I made it happen.
(Very important side note: CCA-Unix was on the arpanet. While I had been given some access to
an Arpanet computer in 1979 by Bob Frankston, the author of VisiCalc, this was my first
day to day access. That access turned out to be the real life-changing event in this story.)
There was a locked room at the back of the office. It contained the computer my code would eventually run on. I was not allowed in the room. Only a very small number of outside companies were allowed to have an IBM PC — Microsoft, UCSD, Digital Research, VisiCorp/Software Arts and a couple of other applications companies.
On this day, 25 years ago, IBM announced their PC. In those days, “PC” meant any kind of personal computer. People look at me strangely when I call an Apple computer a PC. But not long after that, most people took “PC” to mean IBM. Finally I could see what I was coding for. Not that the C compilers were all that good for the 8088 at the time. However, 2 weeks later I would leave to return to school. Somebody else would write the library for my API so that the program would run on the IBM PC, and they released the product. The contract with Mitch required they pay royalties to him for any version of VisiPlot, including mine, so they bought out that contract for a total value close to a million — that helped Mitch create Lotus, which would, with assistance from the inside, outcompete and destroy VisiCorp.
(Important side note #2: Mitch would use the money from Lotus to found the E.F.F. — of which I am now chairman.)
The IBM PC was itself less exciting than people had hoped. The 8088 tried to be a 16 bit processor but it was really 8 bit when it came to performance. PC-DOS (later MS-DOS) was pretty minimal. But it had an IBM name on it, so everybody paid attention. Apple bought full page ads in the major papers saying, “Welcome IBM, Seriously.” Later they would buy ads with lines like Steve Jobs saying, “When I invented the personal computer…” and most of us laughed but some of the press bought it. And of course there is a lot more to this story.
And I was paid about $7,000 for the just under 4 months of work, building almost all of an entire software package. I wish I could program like that today, though I’m glad I’m not paid that way today.
So while most people today will have known the IBM-PC for 25 years, I was programming for it before it released. I just didn’t know it!
Submitted by brad on Fri, 2006-07-28 13:47.
Yesterday I received a Dell 3007WFP panel display. The price hurt ($1600 on eBay, $2200 from Dell but sometimes there are coupons) and you need a new video card (and to top it off, 90% of the capable video cards are PCI-e and may mean a new motherboard) but there is quite a jump by moving to this 2560 x 1600 (4.1 megapixel) display if you are a digital photographer. This is a very similar panel to Apple's Cinema, but a fair bit cheaper.
It's great for ordinary windowing and text of course, which is most of what I do, but it's a great deal cheaper just to get multiple displays. In fact, up to now I've been using CRTs since I have a desk designed to hold 21" CRTs and they are cheaper and blacker to boot. You can have two 1600x1200 21" CRTs for probably $400 today and get the same screen real estate as this Dell.
But that really doesn't do for photos. If you are serious about photography, you almost surely have a digital camera with more than 4MP, and probably way more. If it's a cheap-ass camera it may not be sharp if viewed at 1:1 zoom, but if it's a good one, with good lenses, it will be.
If you're also like me you probably never see 99% of your digital photos except on screen, which means you never truly see them. I print a few, mostly my panoramics and finally see all their resolution, but not their vibrance. A monitor shows the photos with backlight, which provides a contrast ratio paper can't deliver.
At 4MP, this monitor is only showing half the resolution of my 8MP 20D photos. And when I move to a 12MP camera it will only be a third, but it's still a dramatic step up from a 2MP display. It's a touch more than twice as good because the widescreen aspect ratio is a little closer to the 3:2 of my photos than the 4:3 of 1600x1200. Of course if you shoot with a 4:3 camera, here you'll be wasting pixels. In both cases, of course, you can crop a little so you are using all the pixels. (In fact, a slideshow mode that zoom/crops to fully use the display would be a handy mode. Most slideshows offer 1:1 and zoom to fit based on no cropping.)
There are many reasons for having lots of pixels aside from printing and cropping. Manipulations are easier and look better. But let's face it, actually seeing those pixels is still the biggest reason for having them. So I came to the conclusion that I just haven't been seeing my photos, and now I am seeing them much better with a screen like this. Truth is, looking at pictures on it is better than any 35mm print, though not quite at a 35mm slide of quality.
Dell should give me a cut for saying this.
Long ago I told people not to shoot on 1MP and 2MP digital cameras instead of film, because in the future, displays would get so good the photos will look obviously old and flawed. That day is now well here. Even my 3MP D30 pictures don't fill the screen. I wonder when I'll get a display that makes my 8MP pictures small.