Tuesday, October 28, 2008

Petition on Broadband Advertising

I've become rather depressed about broadband advertising. I found it very difficult to discover the web page describing my own ISPs traffic policy. Furthermore if you compare it to this version from January on the Wayback Machine you can see that the headline speed on the "Large" package has gone up from 4Mbit/sec to 10Mbit/sec, but the evening download limit has merely increased from 800MB to 1,200MB, while extra restrictions have been added starting at 10am as well. Somehow that 10MBit/sec upgrade doesn't feel so generous now: when I want to install Fedora 10 I'd better make sure I schedule the download to start after 9pm.

Virgin Media, in common with most other ISPs, says that the few people who make heavy use of their broadband link reduce capacity for everyone else, and that providing truly "unlimited" service for these few would mean higher bills for everyone. They do indeed have a point. If I want truly unlimited service then I'm sure I can get it, for a price. And the fact is that I probably don't want to pay the price. The occasions when I do want a multi-gigabyte download are sufficiently rare that I can put up with scheduling around Virgin's traffic limits.

So why am I depressed about it? Its because my problem with finding Virgin Media's traffic management policy is not unusual. A sample taken from Google found:
  • TalkTalk have a 40GB monthly limit right up there on the front page, although I'm not sure if you can find out how much of your limit you have used this month. What happens when you use it all? Presumably you are cut off until next month.

  • O2 claims "unlimited" usage, but if you search the site for the word "unlimited" you find that excessive use at peak times will lead to warnings and then account termination. They don't define "excessive" or "peak time". I couldn't find a link to this information from their list of broadband features; it certainly wasn't obvious.

  • Tiscali have a similar policy, except that after three warnings they limit your peak time speed. They also don't define what "excessive" and "peak time" mean, and they don't say how long this will last or what the speed limit will be. This page was two not-very-prominent links away from the package features list.

  • Fast actually sells a range of monthly capacity limits. They warn you by email when you hit 90%, and when you go over 100% they throttle you down to 100kBit/sec. Full marks!
So out of 5 providers (including Virgin) we have only one that makes all the limits and policies clear up-front while three try to hide behind weasel words and hard-to-find web pages. This makes it difficult for consumers to figure out what they are buying. Is Tiscali's unstated policy better or worse value for money that one of the Fast packages? Even if its better at the moment, will it still be so next month? As a consumer I have no way of knowing. Worse yet, if I were a technically naive consumer I might not even realise that the question needed asking. "Unlimited" sounds much better than "40Gb monthly limit".

I think that something needs doing about this. However the Advertising Standards Authority have wimped out: they have declared that "unlimited" actually means "95% of users don't hit the limit in any given month". So its hardly surprising that people are confused.

Therefore I have started an on-line petition at the Number 10 web site. If you are a British citizen or resident then I urge you to sign it. The petition calls on the Government to require ISPs to make all caps and limits on their services a prominent part of their advertising. Only when they do so will consumers have a clear choice between different packages.

Sunday, October 26, 2008

SSDs and the return of the root partition

Back in the days when Unix was new to the world computers came with two sorts of mass storage: fast-small-expensive, and slow-big-cheap. A minicomputer typically had one of each, so that frequently-used files could be kept in the fast unit while everything else was kept on the slow one.

Unix was designed with this in mind, which is why to this day most programs on Unix and Linux are found in one of two directories: /bin holds the frequently used ones, and /usr/bin holds the less frequently used ones. A similar arrangement applies to libraries, which are held in /lib and /usr/lib. The idea was that the "root" partition was put on the fast small device, and the "user" partition went on the big one. This led to some other restrictions as well; /bin and /lib together have to have all the software needed for a minimally functioning system, because until all that stuff is going the system can't mount /usr to get at the rest of it.

All that became irrelevant in the age of the Linux PC because the entire system hung off one physical disk. But maybe that is about to change. Solid State Disks (SSDs) are entering the disk world. They have zero mechanical latency and their read speed is blisteringly fast. Write speed is more variable, but the new Intel product is reported to be very fast. It is also small (80GB) and expensive ($600).

So it looks like the time has once again arrived for keeping the commonly used programs and libraries on a small fast disk and everything else on something big and slow. The original root versus /usr division doesn't work for this of course: people want the system to fire up X windows, KDE or Gnome and a bunch of apps, not just a shell prompt. But all of those things will fit very nicely onto one of these SSDs. Better yet, the user files have now been shifted out from /usr (from which it got its name) and put in /home. So this needs zero surgery to the standard Linux layout.

For the average user $600 is a bit steep though. What is actually needed here is something smaller and cheaper. I run a well-populated version of Fedora, and my root partition with all the Fedora packages is under 10GB. So I while I can't imagine blowing $600 (or whatever that is in £s these days) on 80GB of SSD, I could certainly imagine putting a 10GB version in for $100. That would hold the Linux kernel, X Windows and all the apps, with enough room left over for /etc. That would increase the speed of booting up, logging in and starting applications without greatly increasing the cost of the system, especially since that often involves reading lots of different files scattered around the disk. Even better, most of this stuff is only written rarely, and then mostly in the background by system updates. So the current poor write performance of most SSDs doesn't matter.

(Update: I have of course forgotten that by default Unix and Linux keep track of the access time (atime) of files, which means that every time you read something a little metadata write happens. So write performance does matter here).

Looking around, the nearest product to this specification seems to be the OCZ 32GB unit, which retails for a bit over £100 (say, around $170). Thats bigger and more expensive than what I want, but hey, Moore's Law seems to be working so I'll just wait a bit. I also note that all these products seem to be targetted at the laptop market, which makes sense given SSDs other advantages of low power consumption and physical robustness. Maybe they should start thinking about the market for hybrid desktop systems as well.