Robert E. Seastrom writes:
From: Alexis Rosen <alexis@panix.com> [...] This isn't clear to me. Why do you assume a ZIP is likely to be more reliable that a hard disk? ZIPs haven't been around long enough to be sure of this, and HDs are pretty reliable these days.
I think his plan was to boot ramdisk unix from it and then to spin the unit down. Spun-down units are fairly reliable, and besides I think the main thrust here was to replace the drive with something that could be swapped easily for upgrades.
That's more easily done using Vixie's scheme. *My* main thrust is a system with no moving parts (assuming that that's a good way to achieve higher reliability). Of course, both goals are desireable.
Of course I'm not saying that I *Want* to use an HD in this situation; flash is clearly a big win. But I don't see how using a floppy or ZIP improves wins.
With cold-convenient-swappable IDE drawers that let even a kindergartener swap out an IDE hard drive and high quality 100mb hard drives available for like $50 (at this point you're probably paying more for the snazzy mounting kit than you are for the drive), I daresay the Zip and flash solutions are far too expensive for what they buy you. Take a look at the MTBF on your hard drives and then look at the MTBF on power supplies and floppies, and gee... Alexis is dead on here. Pay more, get less...
I think that realistically, finding a stable supply of anything smaller than 1GB is unlikely, unless you're buying large quantities. More to the point, disks for less than $100 are unlikely. But it's not the money that's key here. One service call to a lights-out facility costs lots more than that. Another solution occurs to me. Use dual-anything (floppies, HDs, flash gizmos). Pay someone to modify the BIOS in this small but important way: have it alternate which device it boots from. Let the machine write check a state file kept somewhere else each time it boots. If the same device has booted twice in a row, there's a problem and you notify the NOC that a device has failed. Otherwise rewrite the state file. There's another better solution. It would take a little bit more work but it would be infinitely more useful: Build an ISA card that looks like an MDA adapter, but which sends output to a VT100. (A simple algorithm will produce good results here even when the cursor jumps all over the place.) You also need a gizmo (one exists alread) that makes serial input look like PC keyboard scan codes. And lastly, you need to special-case a long-break so that it causes the ISA card to reset the machine. All of a sudden you've got a working remote console device. This is an extraordinarily useful gizmo, and I'll bet you could sell a million of them. (Everyone who uses Linux, FreeBSD, or NetBSD as a server would buy it, as would the millions of poor souls who run Novell, SCO, etc.) I'd buy fifty of them at $100 apiece, and at that price you'd probably see a gross margin of 300%, even in small quantities, and including the keyboard gizmo. (Now all we need is a better word than "gizmpo" and we've got a real product. :-) Anyone interested in some hardware design work? /a