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 Wed, 2007-10-17 01:44.
Most programs that ask for a password will put in a delay if you get it wrong. They do this to stop password crackers from quickly trying lots of passwords. The delay makes brute force attacks impossible, in theory.
But what does it really do? There are two situations. In one situation, you have some state on the party entering the password, such as IP address, or a shell session, or terminal. So you can slow them down later. For example, you could let a user have 3 or 4 quick tries at a password with no delay, and then put in a very long delay on the 5th, even if they close off the login session and open another one. Put all the delay at the end of the 4 tries (or at the start of the next 4) rather than between each try. It's all the same to a cracking program.
Alternately, you have no way to identify them, in which case rather than sit through a delay, they can just open another session. But you can put a delay on that other session or any other attempt to log into that user. Once again you don't have to make things slow for the user who just made a typo. And of course, typos are common since most programs don't show you what you're typing. (This turns out to be very frustrating when logging in from a mobile device where the keyboards are highly unreliable and you can't see what you are typing!)
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 Mon, 2007-05-07 18:49.
First, let me introduce a new blog topic, Sysadmin where I will cover computer system administration and OS design issues, notably in Linux and related systems.
My goal is to reduce the nightmare that is system administration and upgrading.
One step that goes partway in my plan would be a special software system that would build for a user a specialized operating system “package” or set of packages. This magic package would, when applied to a virgin distribution of the operating system, convert it into the customized form that the user likes.
The program would work from a modified system, and a copy of a map (with timestamps and hashes) of the original virgin OS from which the user began. First, it would note what packages the user had installed, and declare dependencies for these packages. Thus, installing this magic package would cause the installation of all the packages the user likes, and all that they depend on.
In order to do this well, it would try to determine which packages the user actually used (with access or file change times) and perhaps consider making two different dependency setups — one for the core packages that are frequently used, and another for packages that were probably just tried and never used. A GUI to help users sort packages into those classes would be handy. It must also determine that those packages are still available, dealing with potential conflicts and name change concerns. Right now, most package managers insist that all dependencies be available or they will abort the entire install. To get around this, many of the packages might well be listed as “recommended” rather than required, or options to allow install of the package with missing 1st level (but not 2nd level) dependencies would be used. read more »
Submitted by brad on Wed, 2007-04-25 23:54.
As part of my series on the horrors of modern system administration and upgrading, let me propose the need for a universal API, over all operating systems, for accessing data from, and some control of the package management system.
There have been many efforts in the past to standardize programming APIs within all the unix-like operating systems, some of them extending into MS Windows, such as Posix. Posix is a bit small to write very complex programs fully portably but it’s a start. Any such API can make your portability easier if it can’t make it trivial the way it’s supposed to.
But there has been little effort to standardize the next level, machine administration and configuration. Today a large part of that is done with the package manager. Indeed, the package manager is the soul (and curse) of most major OS distributions. One of the biggest answers to “what’s the difference between debian and Fedora” is “dpkg and apt, vs. rpm and yum.” (Yes you can, and I do, use apt with rpm.)
Now the truth is that from a user perspective, these package managers don’t actually look very different. They all install and remove packages by name, perform upgrades, handle dependencies etc. Add-ons like apt and GUI package managers help users search and auto-install all dependencies. To the user, the most common requests are to find and install a package, and to upgrade it or the system. read more »
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, 2007-03-25 13:56.
One of my current peeves is just how much time we spend maintaining and upgrading computer operating systems, even as ordinary users. The workload for this is unacceptably high, though it’s not as though people are unaware of the problem.
Right now I’m updating one system to the beta of the new Ubuntu Feisty Fawn. (Ubuntu is the Linux distro I currently recommend.) They have done some work on building a single upgrader, which is good, but I was shocked to see an old problem resurface. In a 2 hour upgrade process, it asked me questions it didn’t need to ask me, and worse, it asked them at different times in the process. read more »
Submitted by brad on Mon, 2007-03-12 19:08.
I've ranted before about just how hard it has become to configure and administer computers. And there are services where you can hire sysadmins to help you, primarily aimed at novice users.
But we advanced users often need help today, too. Mostly when we run into problems we go to message boards, or do web searches and find advice on what to do. And once we get good on a package we can generally fix problems with it in no time.
I would love a service where I can trade my skill with some packages for help from others on other packages. There are some packages I know well, and could probably install for you or fix for you in a jiffy. Somebody else can do the same favour for me. In both cases we would explain what we did so the other person learned.
All of this would take place remotely, with VNC or ssh. Of course, this opens up a big question about trust. A reputation system would be a big start, but might not be enough. Of course you would want a complete log of all files changed, and how they were changed -- this service might apply more to just editing scripts and not compiling new binaries. Best of all, you could arrange to have a virtualized version of your machine around for the helper to use. After examining the differences you could apply to them to your real machine. Though in the end, you still need reputations so that people wanting to hack machines would not get into the system. They might have to be vetted as much as any outside consultant you would hire for money.
There seems a real efficiency to be had if this could be made to work. How often have you pounded for hours on something that a person skilled with the particular software could fix in minutes? How often could you do the same for others? Indeed, in many cases the person helping you might well be one of the developers of a system, who also would be learning about user problems. (Admittedly those developers would quickly earn enough credit to not have to maintain any other part of their system.)
The real tool would be truly secure operating systems where you can trust a stranger to work on one component.
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 Wed, 2007-02-14 20:12.
Virtualizer technology, that lets you create a virtual machine in which to run another “guest” operating system on top of your own, seems to have arrived. It’s common for servers (for security) and for testing, as well as things like running Windows on linux or a Mac. There are several good free ones. One, kvm, is built into the lastest Linux kernel (2.6.20). Microsoft offers their own.
I propose that when an OS distribution does a major upgrade, it encapsulate your old environment as much as possible in a compressed virtualizer disk image. Then it should allow you to bring up your old environment on demand in a virtual machine. This way you can be confident that you can always get back to programs and files from your old machine — in effect, you are keeping it around, virtualized. If things break, you can see how they broke. In an emergency, you can go back and do things within your old machine. It can also allow you to migrate functions from your old machine to your new one more gradually. Virtual machines can have their own IP address (or even have the original one. While they can’t access all the hardware they can do quite a bit.
Of course this takes lots of disk space, but disk space is cheap, and the core of an OS (ie. not including personal user files like photo archives and videos) is usually only a few gigabytes — peanuts by today’s standards. There is a risk here, that if you run the old system and give it access to those personal files (for example run your photo organizer) you could do some damage. OSs don’t get do a great division between “your” files for OS and program config and “your” large data repositories. One could imagine an overlay filesystem which can only read the real files, and puts any writes into an overlay only seen by the virtual mount.
One can also do it the other way — run the new OS in the virtual machine until you have it tested and working, and then “flip the switch” to make the new OS be native and the old OS be virtual at the next boot. However, that means the new OS won’t get native hardware access, which you usually want when installing and configuring an OS upgrade or update.
All this would be particuarly handing if doing an “upgrade” that moves from, say, Fedora to Ubuntu, or more extreme, Windows to Linux. In such cases it is common to just leave the old hard disk partition alone and make a new one, but one must dual boot. Having the automatic ability to virtualize the old OS would be very handy for doing the transition. Microsoft could do the same trick for upgrades from old versions to Vista.
Of course, one must be careful the two machines don’t look too alike. They must not use the same MAC address or IP if they run internet services. They must, temporarily at least, have a different hostname. And they must not make incompatible changes, as I noted, to the same files if they’re going to share any.
Since hard disks keep getting bigger with every upgrade, it’s not out of the question that you might not keep your entire machine history behind as a series of virtual machine images. You could imagine going back to the computer environment you had 20 years ago, on demand, just for fun, or to recover old data formats — you name it. With disks growing as they are, we should not throw anything away, even entire computer environments.
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.