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Comment: Re:C Needs Bounds Checking (Score 2) 82

by TheRaven64 (#47763563) Attached to: Project Zero Exploits 'Unexploitable' Glibc Bug
It is possible, but for good performance it needs hardware support. We've implemented hardware-enforced bounds checking for C code using our processor. If you only care about accidental bugs and not about a malicious attacker, and don't use threads (or are happy to bound every pointer store with a transactional region), and don't mind that the semantics of C are subtly broken in the kinds of permitted pointer operations, then Intel's Memory Protection Extensions will do the same thing.

Comment: Re:microsofties here is your chance to party (Score 2) 82

by TheRaven64 (#47763559) Attached to: Project Zero Exploits 'Unexploitable' Glibc Bug
The OpenBSD philosophy says that the difference between a bug and a vulnerability is the intelligence of the attacker. There are lots of categories of bugs (null pointer dereferences, integer overflows) that were thought to be unexploitable, right up until someone exploited them. It's the same as with cryptosystems: the fact that you can't break your encryption algorithm doesn't mean that it's secure.

Comment: Re:Progress (Score 1) 261

by TheRaven64 (#47763525) Attached to: Seagate Ships First 8 Terabyte Hard Drive
Your laptop has to be on the same network as your backup machine, but even backing up my laptop over WiFi only takes a couple hours for an incremental backup. I don't have to leave it doing nothing, I just need to leave it on. If I haven't backed up for a while, I might leave it doing the backup overnight, but most of the time I run the backup while I'm working.

Comment: Re:Progress (Score 1) 261

by TheRaven64 (#47763517) Attached to: Seagate Ships First 8 Terabyte Hard Drive
I bought 3 2TB disks just before the flood. About a month ago, they finally became cheaper than I paid. I'd been planning on swapping them out for 4TB disks after 2-3 years, but the 4TB ones are still 50% more than I paid for the 2TB disks. At this rate, 4TB flash will hit the £50 mark before 4TB hard disks...

Comment: Re:Can we get a tape drive to back this up? (Score 1) 261

by TheRaven64 (#47763501) Attached to: Seagate Ships First 8 Terabyte Hard Drive
The difference in cost between tapes and disks hasn't changed much, but the difference in cost of the tape drives to disk drives has changed hugely. You used to be able to get a tape and a drive for only a little bit more than the cost of the disk it would back up. It made sense to use tapes for backups then, because you could afford one tape for the same cost as a backup disk and add new tapes for very little money. Now, if you buy a disk at the sweet spot for price, the tape drive that can back it up to a single tape will cost you about an order of magnitude more than the disk drive. At that point, unless you want a lot more than 10 backups per disk, it isn't worth it.

Comment: Re: Switched double speed half capacity, realistic (Score 1) 261

by TheRaven64 (#47763475) Attached to: Seagate Ships First 8 Terabyte Hard Drive
That's not necessarily true. You can get the same amount of space in a smaller number of tracks around the edge of the disk, so the horizontal movement for the largest seek is going to be smaller. Seek times on mechanical disks are based on three factors. The first two are related: the time it takes to move the head between tracks (proportional to its distance) and the time it takes for the head to settle and be able to be lowered again (dependent on its speed). The third is the time it takes for the correct sector on the track to spin under the head. In the middle, you have fewer sectors per track, so you need to move the head more often (this is where the upper bound on seek times comes from).

Comment: Re:Actually, it does ! (Score 1) 375

by TheRaven64 (#47755217) Attached to: Would Scottish Independence Mean the End of UK's Nuclear Arsenal?

We've actually paid more tax per head, and received less back per head, than England for every one of the last 110 years, which is as far back as the available data goes

A big citation needed there. The last time I looked at the data was in 1998, but back then English tax payers were paying an average of around £100 each for the upkeep of Scotland, if you didn't include the north sea gas revenues.

Comment: Re:My opinion on the matter. (Score 3, Informative) 764

by TheRaven64 (#47754779) Attached to: Choose Your Side On the Linux Divide

The problem is that X was designed for network transparency in a usage model that no longer exists. X is great for network transparency when the server is doing all of the drawing. Unfortunately, the server can't do simple things like antialised line drawing, so people render on the client and then push (uncompressed) pixmaps to the server. A few issues with X11:

Some trivial things, like the fact that command IDs are 8 bits and over half of them are taken up by 'core protocol' things that no one uses anymore. this means that every extension (i.e. the stuff people actually do use) ends up providing a single 'do stuff' command and then a load of subcommands. This limits the number of extensions that you can have loaded and, because the assignment of extensions to command numbers is dynamic, makes intelligent proxies just that little bit harder to write.

There's no easy way for an application to get all of its server-side state. This means that you can't, for example, have the X server crash (or even restart cleanly after an upgrade) and have all clients reconnect and recreate their windows. The Windows and BeOS display servers, for example, have this feature. You also can't tell an application to disconnect from one server and move its windows to another easily. This ought to be basic functionality for a client-server windowing system. There are proxies that try to do this, but they break in the presence of certain (commonly used) extensions.

There is no security model. Any app can get the entire input stream. Keyloggers for X are trivial to write as are programs that inject keystrokes into other applications. Neither requires any special privilege, nor do applications that subvert the display hierarchy (e.g. window managers).

The XRender extension is basically useless. It lets you do server-side compositing, which ought to make things fast. OS X gets a lot of speedup from doing this for text rendering: programs (well, system libraries that programs use) render glyphs in a font to server-side buffers and then the server composites them in the correct place. This doesn't work well with X, because most toolkits aren't set up to do text drawing on the server but everything else on the client (which is needed because the server doesn't provide a rich set of drawing primitives). Fixing this would mean adding something like the full set of PostScript or PDF drawing commands to the server.

XLib is an abomination. It starts with an asynchronous protocol designed for latency hiding and then wraps it up in a synchronous interface. It's basically impossible to use XLib to write an application that performs well over high-latency (more than a few tens of ms) link. XCB is somewhat better, but it's fighting toolkits that were designed around the XLib model so ends up being used synchronously.

None of the network-transparent audio extensions caught on, so your remote apps can't even make notification beeps (worse - they can, but on the remote machine).

If you designed a modern protocol for a network-transparent windowing system, you'd end up with something a lot like a web browser. You'd want PostScript drawing contexts (canvas tags, in HTML5 parlance), server-side caching of images and sound samples (image and audio tags, in HTML5 parlance), and OpenGL contexts. The library would keep a list of all of the contexts that it held on behalf of the program and would be able to recreate them on demand and request that the program reinitialise them. You'd be able to run small snippets of interpreted code on the server (so that things like pressing buttons or opening menus didn't require a full network round-trip - something that DPS and NeWS got right in the '80s, but X11 got wrong). You'd ensure that input events only went to the current view or its immediate parent (if explicitly delegated), or to a program that the user had designated as privileged.

It's possible to do a lot better than X11. Unfortunately, most projects that try seem to focus on irrelevant issues and not the real ones.

Comment: Re:My opinion on the matter. (Score 1) 764

by TheRaven64 (#47754721) Attached to: Choose Your Side On the Linux Divide
There's nothing intrinsically good about the UNIX mindset. For example, UNIX originally put globing in the shell as a work around for not having shared libraries and claimed it was a feature (which led to all sorts of problems - for example */*/* can overflow the command-line argument length limit, whereas a system that had put globing in a shared library would have lazily expanded it in the called program). The problem with the systemd developers is not that they lack the UNIX mindset, it's that they produce utter crap and somehow are able to market it successfully.

Comment: Re: My opinion on the matter. (Score 1) 764

by TheRaven64 (#47754715) Attached to: Choose Your Side On the Linux Divide

That particular use is quite uncommon, but it's increasingly common to stick a recovery root partition in flash (or even in a kernel-embedded RAM disk on a recovery USB drive or similar) so that if you screw up some core configuration you can boot the core system and recover everything else. Keeping it small and self-contained has several advantages. If it's being loaded to RAM on recovery boot, you don't want it to be large and you do want to be able to write the recovery images quickly. If it's in flash (or even a separate FS on the main storage pool) then you don't want it to be too big.

It matters less for big users, who will fix a machine by simply reimaging it and have redundant everything, but if's very useful for a small company that only has a few servers. It's also useful if you're building an appliance and want to be able to have two root partitions that you switch between for atomic updates (boot one, update the other, reboot on the other, always have one bootable root).

Comment: Re:What's the point? (Score 1) 491

by TheRaven64 (#47747249) Attached to: If Java Wasn't Cool 10 Years Ago, What About Now?
Actually, C is used in these cases specifically because it is cross-platform, not for 'platform-specific optimisations'. The core of most of the popular apps on iOS and Android is the same, with a thin layer of platform-specific code, which is Java on Android or Objective-C on iOS. For games, the amount of Java code is typically tiny - create an OpenGL context and pass it to the native code, which is identical on both mobile platforms. This is a big part of the reason why there are so few apps for Windows Phone compared to the other platforms: by forcing WP apps to be entirely managed code, they make it hard to port apps.

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