Robert E. Seastrom writes:
From: Alexis Rosen <firstname.lastname@example.org>
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
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
Anyone interested in some hardware design work?