23 Jun
1998
23 Jun
'98
10:25 p.m.
>> And anyway, a number of S100 cards included
boot ROMs, etc. Those need to
>> be backed up.
> Shure, but where ? Just on a disk ? I already have
the problem
On paper tape, of course. It's reliable (I've
never found a tape that
can't be read), human-readable, and the automatic readers are simple
enough to be repairable...
Jep. Good choice - I still have some paper tabes from the mid
70s in fine condition - but I also know (remembering the past)
how fast they break...
> So, what to use ? Writable CDs ? They have only a
guaranteed
> lifetime of less than 15 years. Tapes ? Maybe - I have some
> PBS Tapes from 1976 and they are still readable, but they are
> 900 and 1600 BpI tapes. Any modern optical and magnetical
You can pack a lot of ROM dumps on a 1600bpi
magtape....
Shure, but 1600 BpI is the first density not readable
to humans. Again insecure.
> Or just put it again on EPROMS - with propper
handling
> EPROMS could survive at least 50+ years - and PROMS
Never!. I'd not trust an EPROM to last longer than
10 years. Nor any
other chip for that matter. Sure, a lot of them will, but some won't. And
if it's the last copy in the world, you've got problems.
EPROMS are a real lot more reliable than any other media.
> (real one not EPROMS without window) should live
even
All chips fail. Bond-outs break, the chip itself
fails, etc. And some
fusible link devices suffer from a problem where the fuses grow back.
I've never seen it myself, but it happens (I've read books on it).
And any magnetic media is crap for long time archival.
Just ask some (ausio) tape fans about tapes from the 60s.
> longer. So just copy them. And beside the
information -
> it will be even more dificult to get a usable 2704 or
> 2708 not already needed for an old computer.
Wait a second. Nobody is suggesting that (a) you
don't keep the EPROM
you've backed up - or indeed that you don't keep using it, or (b) that
you don't stock up on components now. But in 20 years time, it'll be a
lot easier to repair a <whatever> given a ROM dump - even if you have to
kludge in the latest multi-megabit EPROM - than without it.
I'm not interested in the backup, or the content - I just
want to have the particular computer, depending on the content
of the ROM, running. So the backup is just a tool, but it has
to be reliable for long time to reduce backup strategie time.
I found EPROMS running well for 20 years in environments
where a disk wont survive 1 day.
And of course yes, I already have a small component stock
including some 'new' EPROMS from 256 Bytes to 64K (2KBit
... 512KBit).
Gruss
Hans
--
Ich denke, also bin ich, also gut
HRK