27 Jul
1999
27 Jul
'99
5:36 a.m.
The subject pretty much says it all...
I can't seem to figure out how to initialize
a disk with this controller. I'm sure you do
it via the WRITE TRACK command, but I don't
follow what it is that you are supposed to
OUT to the DATA REGISTER. Also, just for
laughs and because I have hundreds of disks
(thanks AOL!), I want to hook up a 3 1/2"
floppy to it. This should be OK, shouldn't
it? How many tracks and sectors-per-track?
What interleave? Finally, I gathered up all
of the CP/M 2.2 stuff I could find on the web...
I've been looking through all of the docs...
They all seem to make the assumption that you
already have a CP/M system disk, on the correct
media, properly formatted and all you need to do
is get your system specific BIOS onto it.
Looking at the BIOS level implementation, it
seems that CP/M doesn't have a native format
command?
Thanks,
Bill Sudbrink
27 Jul
27 Jul
5:50 a.m.
By the way, it has a WD FD1771B floppy
controller chip. I've looked at the chip
directory, Western Digital's web site and
SMC's web site... No luck.
Thanks,
Bill Sudbrink
8:38 a.m.
By the way, it has a WD FD1771B floppy
controller chip. I've looked at the chip
directory, Western Digital's web site and
SMC's web site... No luck.
The 1771 is a single density only controller and not suitable for use with
3.5" disks. You want a board with a 765 (compupro) or 1793 CCS and a raft
of others.
Allison
8:53 a.m.
By the way, it
has a WD FD1771B floppy
controller chip. I've looked at the chip
directory, Western Digital's web site and
SMC's web site... No luck.
The 1771 is a single density only controller and not suitable for use with
3.5" disks. You want a board with a 765 (compupro) or 1793 CCS and a raft
of others.
9:09 a.m.
The 1771 is a
single density only controller and not suitable for use with
3.5" disks. You want a board with a 765 (compupro) or 1793 CCS and a raft
of others.
OK. I'll go 5 1/4". Can you clue me in on how it works? 
9:28 a.m.
At 04:38 PM 7/27/99 -0400, Allison wrote:
The 1771 is a single density only controller and not
suitable for use with
3.5" disks. You want a board with a 765 (compupro) or 1793 CCS and a raft
of others.
Which defines, for the most part, the difference between a 4FDC and a
16FDC. The latter used the 1793 I believe. I've got a copy of the Western
Digital databook that has these ICs in it if someone needs a copy.
BTW, I wrote the formatter for CP/M on the 16FDC (in Turbo Pascal no less
:-)) and it simply loaded up a buffer, then did a write track and stuffed
the buffer with an OUTIR instruction. (the board did wait states so this
worked.) The process involved creating a buffer and using special 8 bit
codes for "sector gap" and "index mark" and "sync mark".
I've long since
given away that code but the person I gave it to is lurking on this list...
--Chuck
9:35 a.m.
BTW, I wrote the formatter for CP/M on the 16FDC (in
Turbo Pascal no less
:-)) and it simply loaded up a buffer, then did a write track and stuffed
the buffer with an OUTIR instruction. (the board did wait states so this
worked.) The process involved creating a buffer and using special 8 bit
codes for "sector gap" and "index mark" and "sync mark".
I've long since
YES! Those codes (and when to fire them) are all I need to know!
According to the 4FDC docs, F7 is write CRC (2 bytes).
If I could just get the format of that buffer...
Thanks,
Bill Sudbrink
9:50 a.m.
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12:31 p.m.
"Bill Sudbrink" <bill(a)chipware.com> wrote:
Hi Bill
I don't recall if the 1771 had an internal or external
data/clock separator. 8" drives came in both flavors. 5.25
and 3.5 only come in the one flavor. The 8 inch controller,
I have for my IMSAI, required the separator to be in the drive
but many later controllers had the separator in the controller.
Even so, you'll have to figure out what gap spacing you'll
need for the sector size you deside to use. I have a table
someplace with some standard arangements. I look around
to see if I can find it.
Dwight
I have the
FD1771 data sheet. Here's a paraphrase of what is says on
formatting.
Excellent! That was exactly what I needed.
Many thanks!
Bill Sudbrink
12:31 p.m.
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6:23 a.m.
On Tue, 27 Jul 1999, Bill Sudbrink wrote:
The subject pretty much says it all...
I can't seem to figure out how to initialize
a disk with this controller. I'm sure you do
it via the WRITE TRACK command, but I don't
follow what it is that you are supposed to
OUT to the DATA REGISTER....
...How many tracks and sectors-per-track?
What interleave? Finally, I gathered up all
of the CP/M 2.2 stuff I could find on the web...
I've been looking through all of the docs...
They all seem to make the assumption that you
already have a CP/M system disk, on the correct
media, properly formatted and all you need to do
is get your system specific BIOS onto it.
Looking at the BIOS level implementation, it
seems that CP/M doesn't have a native format
command?
That final statement sums it up. CP/M was not 'hardware aware' beyond the
very basics needed to read/write data to an existing file system.
A CP/M native 'FORMAT' command did not exist. A transient utility for
disk formatting had to be provided by the hardware/software vendor for
every different controller and drive configuration. Some did provide
better written utilities that could prompt for configuration specific
information to make them more flexible, especially important when mixed
formats started to become more common.
Keep in mind that in the time of CP/M, direct access to the hardware was a
common thing the neither the operating system or the hardware attempted to
prevent this. ...with the occasional exception of the disk controller
that added a 'format disable' DIP switch on the board...
-jim
---
jimw(a)computergarage.org
The Computer Garage - http://www.computergarage.org
Computer Garage Fax - (503) 646-0174
>> Coming soon to www.computergarage.org - the
CBBS/NW on-line archives
>> Coming to VCF III (2-3 October 1999) - CBBS/NW
live!
7:38 a.m.
New subject: Message time stamps
One of the problems I run into is the way messages come into my system
(Win95/Netscape) and get sorted by the time stamp on the message. As just
one example, I have "found" several messages at the bottom of the stack
because it came in with a date stamp of 1969 (or so.) Others stay at the top
of the list because they were stamped with some future date. Just curious if
anyone else runs into the same thing. If so, it would be nice if the
Listserver could time stamp the message with the time it was sent out from
there. (I usually end up sorting out all the messages in the inbox every
1000 - 2000 messages.)
8:45 a.m.
Looking at the
BIOS level implementation, it
seems that CP/M doesn't have a native format
command?
That final statement sums it up. CP/M was not 'hardware aware' beyond the
very basics needed to read/write data to an existing file system. Keep in mind that in the time of CP/M, direct access
to the hardware was a
common thing the neither the operating system or the hardware attempted to
prevent this. ...with the occasional exception of the disk controller
This whas discouraged as it made for non portable software. also due to
the limits of 8080/z80 there was little you can do to prevent direct
hardware access (no prived instructions in the cpu or hardware to enforce
it).
Allison
8:37 a.m.
media, properly formatted and all you need to do
is get your system specific BIOS onto it.
Looking at the BIOS level implementation, it
seems that CP/M doesn't have a native format
command?
Yep! Formatting is a lowlevel task not an operating system primitive.
Too many assumptions of disk layout, controller and IO to have a standard
and it's memory space that is better used for other things. The CP/m
solution is a LLF that runs as a transient. That is usually supplied with
the system by it's vendor... however if your running or want to run other
disks, you generally have to write your own.
What's the controller chip on the 4fdc?
Allison
9061
days inactive
9061
days old
15 comments
7 participants
participants (7)
-
allisonp＠world.std.com -
ard＠p850ug1.demon.co.uk -
bill＠chipware.com -
cmcmanis＠mcmanis.com -
elvey＠hal.com -
jimw＠agora.rdrop.com -
marvin＠rain.org