10 Dec
2003
10 Dec
'03
10:17 p.m.
On Wed, 2003-12-10 at 23:50, Tony Duell wrote:
Presumably there's nothing to stop data being compressed/decompressed at
the 'new' hard drive level, providing the emulator is fast enough to do
this. Unless your ST506 (for the sake of argument) drive contained a
single huge compressed file originally, compression level should be
reasonably good.
Fair call. The shorter cable lengths of IDE *might* be a problem with
mounting in some machines I suppose, but it isn't a biggie. Getting
something that works for the first version is better than nothing :-)
Absolutely. That's how I back up some of my classics with SCSI drives at
the moment :)
It, presumably, would not be difficult to stick a serial port on this
thing for some sort of rudimentary control; there are likely parameters
which it would be handy to be able to set up remotely without delving
inside the classic machine hosting the emulator anyway. Transferring
2-3GB across a serial line isn't really viable (serveral days to
transfer!) but for the more common classic drives in the 10-30MB range I
imagine it's viable.
cheers
Jules
Some controller have links to enable/disable
precompensation. The Adaptec
ACB4000 (I mention that one, since I have an ACW on the bench at the
moment, so the details are stuck in my brain)
Oh, that reminds me - I came across another ACW owner last night.
Waiting to hear what (if any) docs / software he has for it.
4) With a few slight hardware changes (specifically
related to the 'head'
selection and index pulse), the emulator could be connected to the
original ST506 _drive_ and make an image copy of it onto the modern disk.
This would be useful for machines that can't do a low-level format
(again, the HP9133 springs to mind) since such an image copy would copy
the low-level format too. The modern hard disk could then be connected to
a normal emulator and used to replace the ST506 drive in the classic
computer.
That, I think, is a must, compared to having to design something else
entirely to read the data off the drive in the first place. And as you
say, hopefully it isn't too complex to achieve.
Having one
drive per classic doesn't help a) at all, but reliable
drives in the order of 1GB or so can be found for free and are
likely to keep
The simplest hardware would seem to take 2-3Gbytes for a maximum-size
ST506 image. Most will be a lot smaller than that. I think 20-40Gbyte
IDE drives are pretty cheap now.... (I'd still
much rather use SCSI drives as that's what I have
spares of - I don't keep IDE drives lying around)
I don't have either 'spare'. It really comes down to which makes the
hardware interface easier. I'd like to try DMA (see the other message)
this is not too hard on a SCSI drive, I think it's OK on most
modern-ish IDE drives. Point c) about
backup can be rethought. All the interface needs is
*some* way of getting data out of it (and back into it, presumably :)
A really kludgy way to do this is to pull the drive from the
emulator, cable it up to a PC, and copy the image over using dd
or something. Not elegant, but it'll work (remember the data on
the modern drive is stored in normal sectors on said drive, so
a PC can read it, even if it can't make sense of it).