29 Oct
2008
29 Oct
'08
3:10 p.m.
Yah, I done that. The key is to find an MFM drive that has the
same or greater Cylnder/Head geometry: It has to have at least
the same number of cylnders, and at least the same number of
heads.
Keep in mind, though, that geometry alone does *NOT* guarantee
that this will work!! The 9133 seems to be allergic to some
MFM drives-- I could get most Seagate drives to work, for example,
but not NEC's. My fave at the time was the Quantum Q540. I
'wasted' over half the drive, but I had alot of them at the time!
When you format such a drive, you will not have a capacity
greater than the original.[1]
[1] Not quite true for the older 9133 V/X/XV drives. If you have
a 'V' for example, you can replace it with a bigger drive, adjust
the jumpers inside, and format for 10 or 15MB.
-- Jos Dreesen / Marian Capel <jos.mar at bluewin.ch> wrote:
Closely related to the previous post : I actually have an ST419, but is in use inside a
HP9133D.
Looking back to old classiccmp articles indicate that it is not easy to replace the ST419
by other MFM drives of different geometries.
Has this changed ? i.e can somebody report a success in replacing the internal drive of an
HP9133 ?
Jos
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30 Oct
30 Oct
11:53 a.m.
Yah, I done that. The key is to find an MFM drive that has the
same or greater Cylnder/Head geometry: It has to have at least
the same number of cylnders, and at least the same number of
heads.
Right. Some machines seem to check if the drive actually _matches_ (as
opposed to exceeds) the required geometry. They'll attempt to select a
non-existant head and check an error is generated, and so on.
Keep in mind, though, that geometry alone does *NOT*
guarantee
that this will work!! The 9133 seems to be allergic to some
One problem is that HP made a number of devices called a '9133' that had
little internal similarity. They were all hard/floppy disk units, they
all had HPIB interfaces, but that's about it. The earlier ones (9133V,
XV, etc) had separate hard and floppy disk controller boards inside, each
with their own HPIB address and used the Amigo command set. The later ones
(9133H, etc) had one controller with one HPIB address and used the SS/80
command set iIRC.
So saying that something works/doesn't work for a 9133 is somewhat
meaningless. It may work for some versions and not others.
MFM drives-- I could get most Seagate drives to work,
for example,
but not NEC's. My fave at the time was the Quantum Q540. I
'wasted' over half the drive, but I had alot of them at the time!
When you format such a drive, you will not have a capacity
greater than the original.[1]
[1] Not quite true for the older 9133 V/X/XV drives. If you have
a 'V' for example, you can replace it with a bigger drive, adjust
the jumpers inside, and format for 10 or 15MB.
The 9133H has a set of 3 jumpers on the controller board labelled 'Ident
Sea'. These seem to set the controller for different geometries, but I
have no idea what all 16 possiilites actually are. Anyone?
-tony
31 Oct
31 Oct
2:37 a.m.
On Thu, 30 Oct 2008, Tony Duell wrote:
The 9133H has a set of 3 jumpers on the controller
board labelled 'Ident
Sea'. These seem to set the controller for different geometries, but I
have no idea what all 16 possiilites actually are. Anyone?
In such cases I usually throw the firmware image at the IDA disassembler
(we actually have bought two licenses) and look how it works. It shouldn't
be a problem at all to locate the geometries table, and I would simply
patch the firmware to work with the "new" drive.
For example, I have disassembled the firmware of the HP 7958A and found
out how to low-level format a foreign ESDI disk (the original one had
failed) with different geometry (the geometry is read from the drive since
it is ESDI). In this case HP-UX mediainit in guru mode was my friend.
Christian
2:10 p.m.
On Thu, 30 Oct 2008, Tony Duell wrote:
> The 9133H has a set of 3 jumpers on the controller board labelled 'Ident
Make that _4_ jumpers...
Sea'.
These seem to set the controller for different geometries, but I
have no idea what all 16 possiilites actually are. Anyone?
In such cases I usually throw the firmware image at the IDA disassembler For example, I have disassembled the firmware of the
HP 7958A and found
out how to low-level format a foreign ESDI disk (the original one had
failed) with different geometry (the geometry is read from the drive since
it is ESDI). In this case HP-UX mediainit in guru mode was my friend.
I hope you've kept a record of this procedure. It's the sort of thing
others may have to do sometime...
-tony
3:23 p.m.
On 31 Oct 2008 at 21:16, Tony Duell wrote:
The obvious thing to do is to sample the data stream
(either from the
controller wehn writing/formatting, or from a good drive if you want
to copy it) at about 10 times the data rate (that's where the 'high
speed' requirement comes from) and record it in flash memory or
something. Then replay it back to the cotnroller for reading. It's
doable, but getting it all working at 50MHz is not going to be
trivial.
I suspect that 8x oversampling may do the trick; i.e. 40MHz for plain-
Jane MFM. Assume that this will work--will timings really be faster
than is practicable?
Let's see if the math works. Back-of-the-envelope, so you're advised
to double-check my numbers. Assume a brute-force, one-bit-per-sample
implementation.
An ST412 spins at 3600 RPM, giving a rotational period of 16.667
milliseconds. The datarate is 5MHz, so a track can hold about 83335
transitions (less than a 1.44MB floppy track, BTW). We want to
oversample by 8, so we need to sample 666680 times per revolution.
If we use a 16-bit-wide RAM to hold sample data, that's about 42K 16-
bit words, so a 16x65K memory will be more than sufficient and
perhaps allow for a bit faster sampling rate (Tony's 50 MHz) if we
need it.
So, while the bit shifting (or its equivalent) is performed at a 40
MHz clock rate, access to the RAM occurs at 40/16 = 2.5 MHz or 400
nsec--or perhaps 200 nsec while writing (a read is necessary to
"splice" the bit stream). Not bad at all--and a 40MHz shift register
(or its equivalent) is certainly doable using some of the faster TTL-
compatible logic families (e.g. 74AS). And note that you're only
sampling a bit stream whose maximum frequency is 5MHz.
Who wants to build one?
Cheers,
Chuck
1 Nov
1 Nov
2:29 a.m.
On Fri, 31 Oct 2008, Tony Duell wrote:
Of course; it wasn't trivial to find the correct parameters (I think that
I even had started to disassemble the PA-RISC binary of mediainit until I
found the instructions somewhere on the net). After all, it is basically
sending the CS/80 "INIT MEDIA" command with IIRC function number 3 (which
is undocumented).
Christian
Well, if you want to give it a go, I can probably find
an image of the
9133H firmware EPROM. And I should have the memory/IO map of the unit
somewhere. At least that would tell you which address corresponds to
Feel free to email me the firmware. I will then try to do my best :-)
For example, I
have disassembled the firmware of the HP 7958A and found
out how to low-level format a foreign ESDI disk (the original one had
failed) with different geometry (the geometry is read from the drive since
it is ESDI). In this case HP-UX mediainit in guru mode was my friend.
I hope you've kept a record of this procedure. It's the sort of thing
others may have to do sometime...
5676
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