[N8VEM: 19170] Zeta - Floppy question

[Gary Kaufman]

My FDC9266's arrived yesterday, and hooked up a Teac 3.5" using a twisted
cable as drive "00".

Using a 1.44mb floppy, it will format as a 720K only using FDTST.COM If
I change the setup to 1.44mb it won't format at all.
Verify fails after format, but I can read/write/boot the floppy just fine
from CP/M (as a 720K).

System is at 20mhz and rock solid otherwise. Floppy is off of a separate
power supply. No IRQ jumper in place (using polling mode).

Any suggestions or thoughts?

- Gary

[Jim Strickland]

At the risk of dumb, obvious questions, is your drive perhaps a 720k drive? -JRS

[Gary Kaufman]

Jim -

Hardly a dumb question, I had trouble booting a system a few years ago
until I realized that the 5.25" drive I had was an 80 track type!

I've tried both Teac FD-235HF and Teac FD-235HG types. Both are 1.44mb
drives although the "HG" also supports 360rpm rotational speed.

I've been playing a bit more, and find that if I drop the cpu clock to 8mhz
I can format/read/write as a 1.44mb floppy but the verify function still
fails.

I'm curious that everything else works fine at 20mhz - but will try
swapping out some of the TTL for either F/AS/AHCT types and see if that
fixes the problem.

Does the Verify function of FDTST work for other folks?

- Gary

Post by Jim Strickland
At the risk of dumb, obvious questions, is your drive perhaps a 720k drive? -JRS

[Wayne Warthen]

The verify function of FDTST is a kind of stupid (I can say this since I
wrote it). The verify function compares every sector read to the contents
of the current buffer. If you have not seeded the buffer with a byte
pattern that is the same pattern that will be read from every sector, the
verify will fail. The intended use is to fill the buffer with a byte
pattern, then write that pattern to all sectors, then use the verify
function to read back the sectors with the buffer still containing the same
pattern.

Sorry if this was the source of your trouble.

---Wayne

Post by Gary Kaufman
Jim -
Hardly a dumb question, I had trouble booting a system a few years ago
until I realized that the 5.25" drive I had was an 80 track type!
I've tried both Teac FD-235HF and Teac FD-235HG types. Both are 1.44mb
drives although the "HG" also supports 360rpm rotational speed.
I've been playing a bit more, and find that if I drop the cpu clock to
8mhz I can format/read/write as a 1.44mb floppy but the verify function
still fails.
I'm curious that everything else works fine at 20mhz - but will try
swapping out some of the TTL for either F/AS/AHCT types and see if that
fixes the problem.
Does the Verify function of FDTST work for other folks?
- Gary

Post by Jim Strickland
At the risk of dumb, obvious questions, is your drive perhaps a 720k drive? -JRS

[Gary Kaufman]

Wayne -

Thanks, that makes much more sense, and FDTST is quite a useful program.

I still appear to have some timing/speed problem that prevents formatting
as a 1.44mb floppy unless I lower the clock speed to 8mhz. I'll try
swapping some of the LS for AHCT/HCT/F versions and see if that makes a
difference - or just run the board at 8mhz.

Thanks again!

- Gary

Post by Wayne Warthen
The verify function of FDTST is a kind of stupid (I can say this since I
wrote it). The verify function compares every sector read to the contents
of the current buffer. If you have not seeded the buffer with a byte
pattern that is the same pattern that will be read from every sector, the
verify will fail. The intended use is to fill the buffer with a byte
pattern, then write that pattern to all sectors, then use the verify
function to read back the sectors with the buffer still containing the same
pattern.
Sorry if this was the source of your trouble.
---Wayne

Post by Gary Kaufman
Jim -
Hardly a dumb question, I had trouble booting a system a few years ago
until I realized that the 5.25" drive I had was an 80 track type!
I've tried both Teac FD-235HF and Teac FD-235HG types. Both are 1.44mb
drives although the "HG" also supports 360rpm rotational speed.
I've been playing a bit more, and find that if I drop the cpu clock to
8mhz I can format/read/write as a 1.44mb floppy but the verify function
still fails.
I'm curious that everything else works fine at 20mhz - but will try
swapping out some of the TTL for either F/AS/AHCT types and see if that
fixes the problem.
Does the Verify function of FDTST work for other folks?
- Gary

Post by Jim Strickland
At the risk of dumb, obvious questions, is your drive perhaps a 720k drive? -JRS

[Jim Strickland]

Yeah, my zeta has 74f logic pretty much throughout. It's happy at 20mhz now, but it was a little rocky getting there. It was the first computer I ever soldered, though. The zeta is very forgiving.

-JRS