Source for remote control 13A plugs ...

That's because it journals.

They may call it an intent log but it is a journal.

The veritas file system we were using also had an intent log so its not something new. In fact Sun acquired the source for it when the bought out SVr5 in the eighties.

Oh, I had two or three in my time. Mainly overheated and crashed completely due to fan failures.

A power cycle got them going long enough to do emergency access stuff before we could get to them and replace the fans.

A lot depends on what access you have to e.g. serial ports.

A lot of times we couldn't TELNET in and if we didnt have reverse terminal servers to use as serial boot devices, we would power cyccle if they had frozen and wouldn't accept a network connection.

However that generally didn't work if they were FSCKed..reverse terminal servers were better as you could with the error messages in boot..and go down with the right bits of hardware.

No. A journal keeps filesystem metadata (the data such as directories and inodes) which is required to ensure the filesystem remains self-consistent. It doesn't care about the file contents. The ZFS intent log is for POSIX commit symantics, i.e. when you explicitly flush a file to disk (and it does care about file contents, and some metadata changes). ZFS has no need to journal by design, as the filesystem metadata is never inconsistent on disk at any point in time (so the journal would always be empty if it had one, which is why it doesn't have one, nor an fsck command as there can never be any journal to replay).

There's no veritas file system source in SVR4. (There's no such thing as SVR5 -- it was a SCO marketing term only which came from their doomed project to merge SVR4 and HP-UX.) AIX's filesystem and volume management was developed for them by veritas, and that probably has internal similarities with veritas's, but isn't part of the SVR4 sources, and Sun don't have it. The main SVR4 filesystem, ufs, is derived from the Berkely Fast Filesystem, via SunOS 4, which AT&T paid Sun to port into SVR4 (as part of the SunOS 4 memory management system port to SRV4 which AT&T commissioned Sun to do). There was no journaling in SVR4 when Sun and AT&T finished producing it, and Solaris split off. Sun added journaling to Solaris around 1994 as part of the Disksuite add-on, and moved the journaling into base Solaris starting with Solaris 7 (1998?). If journaling appeared in SVR4 source, it would have been done by AT&T, Novell, or SCO at some later date. SVR3 and earlier SysV unixes used the System V filesystem as the default filesystem. (Most vendors created their own variants of the System V filesystem towards the end of SVR3, as the basic one had a number of increasingly unacceptable restrictions, such as 32k or 64k max number of files (or rather inodes), fairly small max filesize by today's standards, small max filesystem size, no symlinks, etc.)

That, and it was time for you to run the vacuum cleaner round the office after the programmers had gone home for the day.

If you want to define it that way, however the veritas system could put the data into the log if you asked it to.

Your unix knowledge is a bit lacking. SVr5 predates SCO by a good margin. And I know there was veritas source code in it as I had the source code. In fact I worked with the engineers to customise SVr5 to do what we needed as well as designing some STREAMs modules to do pseudo real time stuff. I think you will find it was univel (sp?) hat was spun off from AT&T that developed SVr5. One of the main things they did was to compartmentalize the kernel so it could get B2 (IIRC) security.

BTW all the System X exchanges have Veritas file systems running on some of the hardware, I put it there.

Unlikely. I've been working on the System V source code since SVR3.0 (on the first commercial unix source allowed into the UK by Bell labs).

I'm suspecting you're mixing that up with up System V Release 4. SVR5 came out of the 3DA project between SCO (just after they bought the SVR4 source code from Novell) and HP. 3DA died (just as I predicted it would at the time), but SCO continued using the SVR5 name for Unixware 7, the merging they did between Openserver 5 (SVR3.2) and Unixware 2 (SVR4) at the time. No one else used the term - unlike SVR4, it was not a recognised industry standard, and it's died along with SCO - they never made a viable business out of any of the Unixware releases. SCO itself long predates any System V unix - it goes back to System III unix on which Xenix was based (a joint effort between SCO and Microsoft at the time, amazingly now).

AT&T sold SVR4 and USL (Unix Systems Labs) to Novell (which is where the Univel word comes from), who then sold it to SCO. SCO thought they could create SVR5 as an industry standard like SVR4 was, but no one else in the industry was interested. In subsequent conversations with former SCO employees, apparently SCO thought that SVR4 was effectively Solaris, and they were buying Solaris. This was very wrong. Solaris never was entirely SVR4, and it had moved on way past SVR4 with a fully preemptive kernel, very many multi-processor support, and realtime scheduling, and rock solid threads support, which SVR4 (and hence SVR5 too) never caught up with. (Since you mention STREAMS, that was one of the major areas which Sun had to do significant work on to make it properly preemptive, multi-threaded, multi-processor, and support realtime processes, which the stock SVR4/5 STREAMS framework couldn't get close to doing.)

Veritas sell their filesystem technology for a wide variety of unixes including SVR4 flavours, but they've never put it into the SVR4 codebase. It very likely exists in various private branches off the SVR4 codebase for specific manufacturer's systems, where those manufacturers have purchased it from veritas (now Symantec). AIX is one such (although that's originally branched from SVR3, not SVR4, and quite possibly HP-UX which is similarly originally branched from SVR3).

There are other operating systems other than Windows ...

... many of which are equally unhappy about having the power killed...

Windoze (and I'm sure most of the others) can be shut down remotely, which is better for the health of the file system.

Andy

On the original subject

Lidl have a pack of 4 on thursday with remote controler.

You will prolly have to input your postcode first?

Well, B&Q and the 3pack "Home-Easy" on/off plugs are now chez Jethro.

Quite impressed with the Home-Easy range ... home automation never seemed so easy. I particularly liked the SMS-driven controllers, although I can't think of a use right now.

Just to explain why I wanted the plug in the first place .... I've wanted to set up a "download" server for ages now, which I can whack a bitorrent, or large FTP onto, and just leave it running. However there is no way on Gods green earth I'm going to leave a Windows box open to the internet 24/7, firewall or not. Which proved a good excuse to teach myself Linux (Ubuntu). However, due to various struggles getting a wireless USB key working the whole project took a *little* longer than I told the missis. To be fair, she'd been very patient, and didn't harp on about the loss of the front room. However after 4 months it was a little more than a joke, and I was given an ultimatum ... so the PC went into the loft, without being 100% prepared, or tested (at least I can NXMachine into it).

It's "frozen" a couple of times, and required a restart (after which it works fine), and having to get the loft ladder down etc etc etc - especially if I'm not at home (I remote in from work, and the missis can't climb a ladder). So I thought the remote was the best solution - although it remains very much a "nuclear" option.

Fingers crossed, the machine stayed up 10 days before I fitted the plug, so it's possible that the problems been fixed by one of the updates I installed recently.

Thanks for everyones help - hope you all enjoyed the debate !

I have had several windows boxes open to the internet 24/7 for years and never had a successful attack on them, even when running utorrent and emule. The security problems are very exaggerated.

Don't mention that in a linux group.. they will savage you for being a troll.

If yours was crashing after a few days it was well broken.

Depends on the firewall. I have one Windows box like that; been on 24/7 for about 4 years.

Or it's an overheating/underheating/PSU/other_hardware problem. I have FreeBSD boxes that have stayed up for months at a time, only rebooted because of power cuts or upgrades. But then Linux *is* just a jumped up UNIX wannabe!