31 Aug
2010
31 Aug
'10
4:13 p.m.
Hi guys,
I'm toying with the idea of doing an MFM/RLL hard drive bolt-on for the
DiscFerret (seeing as the DF hardware is basically done now -- I'm just
doing a final design check before I send the PCBs off for manufacturing).
Problem is, I don't have a drive to play with.
Does anyone have any or all of the following kicking around?
- MFM or RLL hard drives. I could do with one or two of these;
anything's good, as long as it has an ST506-style interface (that is,
straight MFM/RLL with no funny business) and is believed to work. I'm
ideally aiming for something "of reputable manufacture" -- so not a
Kalok Octagon!
- Cable kit for the above. So that's the Data and Control cables --
edge connector to IDC plug.
- MFM/RLL controller to match the drive. Anything goes here -- e.g.
Western Digital WD100x series, DTC, Omti... as long as I can make it
work with the drive for long enough to format the drive and 'dd' some
data onto it. I'll even consider SCSI-to-MFM bridges if they can be
relatively easily tied to a modern PCI, PCIe or USB SCSI card (say, an
AHA2940).
I'm happy to pay reasonable market value for the above, but that doesn't
extend to paying ?390 for drive-on-its-own (read: drive that's had the
PCB removed and is basically useless) on "that online auction site"...
Thanks,
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
31 Aug
31 Aug
5:48 a.m.
Hi guys,
I'm toying with the idea of doing an MFM/RLL hard drive bolt-on for the=20
DiscFerret (seeing as the DF hardware is basically done now -- I'm just=20
doing a final design check before I send the PCBs off for manufacturing).
Problem is, I don't have a drive to play with.
Does anyone have any or all of the following kicking around?
- MFM or RLL hard drives. I could do with one or two of these;=20
anything's good, as long as it has an ST506-style interface (that is,=20
straight MFM/RLL with no funny business) and is believed to work. I'm=20
ideally aiming for something "of reputable manufacture" -- so not a=20
Kalok Octagon!
Alas not. Well, actually, I have a number od such drives, but I have even
more classic computers that use them. So nothing 'spare'
- Cable kit for the above. So that's the Data and Control cables --=20
edge connector to IDC plug.
Err, the connectors are still avaialble (easily...) So is IDC ribbon
cable. And I assume you own a metalwork vice, since it's so useful for
other things. Which means you could make the cables in less time that
it's taken me to type this.
- MFM/RLL controller to match the drive. Anything
goes here -- e.g.=20
Western Digital WD100x series, DTC, Omti... as long as I can make it=20
What do you want as the host computer interface? I am pretty sure I can
find the odd ISA bus one, but what would you use that with?
-tony
1 Sep
1 Sep
11:49 a.m.
Hi guys,
I'm toying with the idea of doing an MFM/RLL hard drive bolt-on for the=20
DiscFerret (seeing as the DF hardware is basically done now -- I'm just=20
doing a final design check before I send the PCBs off for manufacturing).
Problem is, I don't have a drive to play with.
Does anyone have any or all of the following kicking around?
- MFM or RLL hard drives. I could do with one or two of these;=20
anything's good, as long as it has an ST506-style interface (that is,=20
straight MFM/RLL with no funny business) and is believed to work. I'm=20
ideally aiming for something "of reputable manufacture" -- so not a=20
Kalok Octagon!
Alas not. Well, actually, I have a number od such drives, but I
have even
more classic computers that use them. So nothing 'spare'
- Cable kit for the above. So that's the
Data and Control cables --=20
edge connector to IDC plug.
Err, the connectors are still avaialble (easily...) So
is IDC ribbon
cable. And I assume you own a metalwork vice, since it's so useful for
other things. Which means you could make the cables in less time that
it's taken me to type this.
- MFM/RLL controller to match the drive.
Anything goes here -- e.g.=20
Western Digital WD100x series, DTC, Omti... as long as I can make it=20
What do
you want as the host computer interface? I am pretty sure I can
find the odd ISA bus one, but what would you use that with?
-tony
1:50 p.m.
On 31/08/10 13:48, Tony Duell wrote:
ISA would be fine. Basically I need something I can hook up to a PC
(either my clunky old 386-with-ISA-IDE-controller or something more
recent) that will allow me to format the drive, and write something to
it. Bulk-erase by holding WR_GATE active and WR_DATA low and
track-stepping, then format using the controller. Read the data back
with the Ferret and see what's there (probably an MFM bitstream based on
the Seagate format recommendations).
SCSI would be fine too, but then I'd have to buy a SCSI card... :)
And it'd have to be capable of talking to a (relatively) modern SCSI
card (PCI interface; Adaptec AHA2940 or something like that).
At the moment, it's a "this would be really cool to have" type feature
addition -- it doesn't seem that much harder to do MFM HDD dumping, and
would make the DiscFerret the only imager capable of doing this at
transition level. SMD might also be an option... later.
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
Alas not. Well, actually, I have a number od such
drives, but I have even
more classic computers that use them. So nothing 'spare'
Yeah, I've heard of a lot of folk in the same situation.
I'm actually getting slightly tempted to hunt down a 1st-gen Acorn
Archimedes with Acorn-installed ST506 hard drive. That would give me a
drive and a known-good controller.
Err, the connectors are still avaialble (easily...) So
is IDC ribbon
cable. And I assume you own a metalwork vice, since it's so useful for
other things. Which means you could make the cables in less time that
it's taken me to type this.
Yes I could make a cable, but it's easier to use a ready-made one (if
you can find one) than it is to make one up specially :)
- MFM/RLL
controller to match the drive. Anything goes here -- e.g.=20
Western Digital WD100x series, DTC, Omti... as long as I can make it=20
What do you want as the host computer interface? I am pretty sure I can
find the odd ISA bus one, but what would you use that with? 
2:03 p.m.
ISA would be fine. Basically I need something I can
hook up to a PC
(either my clunky old 386-with-ISA-IDE-controller or something more
recent) that will allow me to format the drive, and write something to
it. Bulk-erase by holding WR_GATE active and WR_DATA low and
track-stepping, then format using the controller. Read the data back
with the Ferret and see what's there (probably an MFM bitstream based on
the Seagate format recommendations).
My understanding is that there's enough variation in the low level
formatting between controllers that MFM drives aren't very portable.
That could be interpreted as timing differences between models, or as
timing variations in different instances of the same model, or even
actual structure differences. I don't know which was meant by whatever
source told me this long ago.
Even assuming it is true, it doesn't necessarily kill your concept,
though it might make implementation a hell of a lot more exciting.
De
2:21 p.m.
On 01/09/10 22:03, Dennis Boone wrote:
My understanding is that there's enough variation
in the low level
formatting between controllers that MFM drives aren't very portable.
That could be interpreted as timing differences between models, or as
timing variations in different instances of the same model, or even
actual structure differences. I don't know which was meant by whatever
source told me this long ago.
There are format differences. Different CRC implementations, different
encoding rules (gap lengths and so on), slightly different ways of
encoding the data (LSB-first, MSB-first, bit-sequential, staggered),
interleaving, ......
The fun part is figuring out what those differences are, then 'teaching'
the software how to identify them, and make sense of what's there. Same
as I did with MagScan (which is still tied up in Licensing Hell and very
close to being rewritten from scratch).
Even assuming it is true, it doesn't necessarily
kill your concept,
though it might make implementation a hell of a lot more exciting.
My life would be FAR more boring without all these fun and interesting
puzzles :)
I'm not above "blackbox" reverse engineering if it proves necessary.
Change one byte, see what happens, that sort of thing.
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
3:11 p.m.
On 1 Sep 2010 at 22:21, Philip Pemberton wrote:
I'm not above "blackbox" reverse
engineering if it proves necessary.
Change one byte, see what happens, that sort of thing.
...and then after you've cracked the MFM/RLL/ARLL hard drives, you
can tackle the various flavors of ESDI...
Fun!
--Chuck
3 Sep
3 Sep
3:39 a.m.
On 1 September 2010 22:03, Dennis Boone <drb at msu.edu> wrote:
My understanding is that there's enough variation
in the low level
formatting between controllers that MFM drives aren't very portable.
That could be interpreted as timing differences between models, or as
timing variations in different instances of the same model, or even
actual structure differences. ?I don't know which was meant by whatever
source told me this long ago.
This was as I recall it, too, but back in the '80s I did occasionally
successfully move ST506 MFM and RLL drives between controllers. Always
in fairly generic IBM-branded kit, though.
--
Liam Proven ? Info & profile: http://www.google.com/profiles/lproven
Email: lproven at cix.co.uk ? GMail/GoogleTalk/Orkut: lproven at gmail.com
Tel: +44 20-8685-0498 ? Cell: +44 7939-087884 ? Fax: + 44 870-9151419
AIM/Yahoo/Skype: liamproven ? MSN: lproven at hotmail.com ? ICQ: 73187508
3:38 a.m.
On 1 September 2010 21:50, Philip Pemberton <classiccmp at philpem.me.uk> wrote:
On 31/08/10 13:48, Tony Duell wrote:
Might be able to help you there, actually. Not sure of running
condition but I think I still have my A305 + 1MB RAM upgrade.
--
Liam Proven ? Info & profile: http://www.google.com/profiles/lproven
Email: lproven at cix.co.uk ? GMail/GoogleTalk/Orkut: lproven at gmail.com
Tel: +44 20-8685-0498 ? Cell: +44 7939-087884 ? Fax: + 44 870-9151419
AIM/Yahoo/Skype: liamproven ? MSN: lproven at hotmail.com ? ICQ: 73187508
Alas not. Well, actually, I have a number od such drives, but I have even
more classic computers that use them. So nothing 'spare'
Yeah, I've heard of a lot of folk in the same situation.
I'm actually getting slightly tempted to hunt down a 1st-gen Acorn
Archimedes with Acorn-installed ST506 hard drive. That would give me a drive
and a known-good controller.
5006
days inactive
5009
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8 comments
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participants (6)
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ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
classiccmp＠philpem.me.uk -
drb＠msu.edu -
jws＠jwsss.com -
lproven＠gmail.com