10 Jan
2012
10 Jan
'12
1:08 p.m.
Josh Dersch <derschjo at mail.msu.edu> wrote:
I have both a 16FDC and a 64FDC (for the moment) and
right now I have it
wired to a single
5.25" drive (w/proper termination). I've
tried three different drives --
a Tandon TM-100, an
unmodified 1.2M 5.25" drive, and one that's
modded to spin at 300rpm.
Same exact behavior on all three.
Sounds like you have the basics covered. Are you running your Z-80 CPU
board at 4MHz?
Though I'd find it unlikely that *both* controllers would be seriously out
of adjustment, I'd also check that the data separator oscillator is at the
right frequency. Instructions are in the FDC user manuals for checking and
adjusting that.
10 Jan
10 Jan
11 p.m.
I have both a 16FDC and a 64FDC (for the moment) and
right now I have
it wired to a single 5.25" drive (w/proper termination). I've tried
three different drives -- a Tandon TM-100, an unmodified 1.2M 5.25"
drive, and one that's modded to spin at 300rpm. Same exact behavior on
all three.
Are you attempting to format single or double sided? WHICH is your
TM-100?
Are you attempting to format 40 track or 80?
Although most 1.2M drives can be configured for 80 track DOUBLE (NOT
"HIGH"!) density, it adds additional unnecessary variables. 1.2M is the
WRONG drive for that FDC port.
It might be feasible to cable the 1.2 (or a 1.4M!) drive to the 8" port,
but don't even try until you get the "normal" stuff working.
When it "won't read", in what way? Is it failing to see sectors and
formatting? Or is it just unhappy with the directory structure and/or
"boot" sector?
There are numerous format variations possible with Cromemco. Most
[5.25"] have 10 sectors of 512 bytes per sector, and the index and data
gaps are "not easy" for a PC FDC to read. However, a disk formatted to
10 x 512 on a PC, with appropriate content in the "boot" sector is
readable by Cromemco, and solves SOME data interchange issues.
11 Jan
11 Jan
9:03 a.m.
On 1/10/2012 3:00 PM, Fred Cisin wrote:
It's a TM-100-2A (originally from an IBM PC). Formatting single sided
at the moment, 40 tracks.
I have both a
16FDC and a 64FDC (for the moment) and right now I have
it wired to a single 5.25" drive (w/proper termination). I've tried
three different drives -- a Tandon TM-100, an unmodified 1.2M 5.25"
drive, and one that's modded to spin at 300rpm. Same exact behavior on
all three.
Are you attempting to format single or double sided? WHICH is your
TM-100?
Are you attempting to format 40 track or 80?
Although most 1.2M drives can be configured for 80 track DOUBLE (NOT
"HIGH"!) density, it adds additional unnecessary variables. 1.2M is the
WRONG drive for that FDC port.
It might be feasible to cable the 1.2 (or a 1.4M!) drive to the 8" port,
but don't even try until you get the "normal" stuff working.
Good to know. Tried the 1.2M drives because I had them lying around as
an alternative to the Tandon.
When it "won't read", in what way? Is it failing to see sectors and
formatting? Or is it just unhappy with the directory structure and/or
"boot" sector?
RDOS (the ROM monitor) says "Err-H 34" on a read which (if I recall the
manual correctly) translates as "Record Not Found". I can't remember
what I get for writes, I'll have to try it again when I get a chance
(hopefully in the next few days.)
There are numerous format variations possible with Cromemco. Most
[5.25"] have 10 sectors of 512 bytes per sector, and the index and data
gaps are "not easy" for a PC FDC to read. However, a disk formatted to
10 x 512 on a PC, with appropriate content in the "boot" sector is
readable by Cromemco, and solves SOME data interchange issues.
Ok, thanks for the tip. I'm currently trying to write disk images using
Dave Dunfield's RDOS transfer utilities (it pushes data to the ROM
monitor over the serial port to write the floppies, and uses a copy of
CDOS's "INIT" program to format them) but it'll be useful at some point
to be able to do this from a PC. I figured removing the PC-floppy part
of the equation and focusing just on the Cromemco controller side of
things would make things easier...
- Josh
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