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Need some help with 8 inch floppy drive...

Al Kossow

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* Has anyone succesfully restored and run any of the floppy images for IBM Displaywriter on bitsavers?

The single-sided disks have been tested, the recently added double-sided disks have not.

As Chuck says, you really should be using Imagedisk for testing.

and.. be EXTREMELY careful with the disk that was sent to you. Like I said, no double-sided disk images have been verified
to work and it would be really bad if the one you were given was destroyed.

also, the diagnostic disks require one track to be completely blank, which requires you to bulk-erase the diskette before copying to it.
 

MikeS

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Pictures on the web seem to suggest that the Displaywriter uses single-sided disks (Type 1); if the drives are in fact single-side drives then they will not normally be able to read double-sided disks (Type 2 or 2D) such as the SA-851 might create, because the index holes are in different locations.
 
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Adventurer

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The single-sided disks have been tested, the recently added double-sided disks have not.

As Chuck says, you really should be using Imagedisk for testing.

and.. be EXTREMELY careful with the disk that was sent to you. Like I said, no double-sided disk images have been verified
to work and it would be really bad if the one you were given was destroyed.

I wil, first thing I will do - make a backup of the contents on the Displaywriter itself. However, the floppy has not arrived yet, and I'm afraid it might be lost in transit...
 

Adventurer

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Pictures on the web seem to suggest that the Displaywriter uses single-sided disks (Type 1); if the drives are in fact single-side drives then they will not normally be able to read double-sided disks (Type 2 or 2D) such as the SA-851 might create, because the index holes are in different locations.

I think there might be a problem - it is possible, that Displaywriter will not take DS/DD floppies, only SS/DD. At least drive doors have marks 1/2D. I should have been more careful with purchasing 8 inch floppies, and should not have bought DS/DD format at all, whicn I think will have no use for me now.

Besides, it was probably not the best idea to write single side images on a double sided floppy - I'm not sure if it works that way at all. Whatever, now it is time to order SS/DD floppies for further testing and troubleshooting...
 

modem7

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Modem7,
Could this be bypassed using the DOS driver "driver.sys" to give formatting info to programs like format?
Also can't you can define format parameters on the command line for format.com:
https://technet.microsoft.com/en-us/...(v=ws.11).aspx
So IIRC this should work: format d: /a:1024 /t:77 /n:8 where d is your 8" drive. Since you specify /n: I don't BELIEVE you need the /8 switch. Please note this is for MS-DOS version of the format.com and not the windows version.
My use of an 8" drive in DOS was short-lived; the novelty wearing off quickly. Maybe others here (for whom the novelty has yet to wear off) will experiment and report results.

If it does not work, the impact may be low. I seem to recall that DOS keeps data together as much as possible, for performance reasons. If that is the case, then post format, a problem may only be experienced if someone tries to fill the floppy to near capacity.

However, the floppy has not arrived yet, and I'm afraid it might be lost in transit...
I posted it almost three weeks ago. It does seem hard to believe that a large envelope would take that long to get from Australia to Europe. Maybe customs intercepted it and stuck the floppy on their wall as a reminder of the good old days when they used CP/M systems. Maybe the kangaroo got lost.
 

Adventurer

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My use of an 8" drive in DOS was short-lived; the novelty wearing off quickly. Maybe others here (for whom the novelty has yet to wear off) will experiment and report results.

If it does not work, the impact may be low. I seem to recall that DOS keeps data together as much as possible, for performance reasons. If that is the case, then post format, a problem may only be experienced if someone tries to fill the floppy to near capacity.


I posted it almost three weeks ago. It does seem hard to believe that a large envelope would take that long to get from Australia to Europe. Maybe customs intercepted it and stuck the floppy on their wall as a reminder of the good old days when they used CP/M systems. Maybe the kangaroo got lost.

Too bad about the floppy, I still hope it might arrive, since I'm not making great progress so far with Displaywriter images on Bitsavers...

As for format with line "/a:1024 /t:77 /n:8", the problem is that switch "a" has been implemented starting with Windows 2000, it can not be run on MS-DOS 5.0 I have now. Still, I'm trying third party utilities, the results are coming in.
 
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Adventurer

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I'm still getting nowhere.

ImageDisk - I can successfully format/verify/read in DS/DD format, that is, until I have to write an image.
P1001354.jpg

As a matter of fact I can successfully write only SS/SD format, SS/DD is not working - do not really understand now.
It seems that ImageDisk starts to write SS/DD image first as SS/SD, then, after track 6 it tries to switch to SS/DD format with no success - see attached picture:

P1001353.jpg

As for writing SS/SD image - at first, everything seems to be good, no errors, disk seems to be written correctly:
P1001343.jpg

However, when I try to copy disk image to hard drive, nothing works:
P1001344.jpg

I started to think that there might be a drive head alignment problem, however, freshly formated disk shows no errors in Imagedisk, when testing read/write/seek, I manually tested all tracks:
P1001346.jpg
 
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Adventurer

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Here are the results of testing format/writing in MS-DOS mode. So far the only uility, which seems to work on formatting this disk, is Fdformat. It can format it as 620K disk, or 1.2 MB:

P1001359.jpg

Both formats allow read/write/copy with no problems. Even sys.com works on 8 inch drive.

P1001357.jpg

However, this is where the fun ends - if I do one of the following:

* Take out the floppy
* Restart/Switch off the PC

Then it is no longer readable, and I get either "sector not found" error or generic drive failure error. Actually it seems that as soon as the drive stops spinning, my data is gone. Only once I could get the contents of the floppy with one retry, and there were two small files on it. In all other occasions I had to format the floppy again to get it to work. Could there be a problem with a drive seek unable to return to exactly the same position when they are moved away?
 

Adventurer

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Open up the drive box, look at the top of the drive. Single-sided drives have only a pad instead of a head on top.

I will do that, but first I need to be able to write and read the Displaywriter images, so far - one big FAIL.

So far I can only read/write DS/DD format:

Heads: 77
Sectors per track: 8
Sector size: 1024
Sides: 2
Data rate: 500K MFM

Low level format - PASS
Write - PASS
Read - PASS

Other formats tried, but failed:

DS/SD

Cylinders: 77
Sectors per track: 26
Sector size: 128
Sides: 2
Data rate: 250K FM

Low level format - PASS
Write - PASS
Read - FAIL, can read only first sector of each track

SS/SD

Cylinders: 77
Sectors per track: 15
Sector size: 256
Sides: 1
Data rate: 250K FM

Low level format: PASS
Write : PASS
Read: FAIL, can read only first sector of each track

What even more puzzles me, is that SS/SD images of Displaywriter software seem to be written with 500K instead of 250 - I have to use translation to 250 in ImageDisk settings to be able to write the image, but still - it fails with the same problem - can read only first sector of each track.

Could anyone help me with this issue? It seems I am stuck right there...
 

Al Kossow

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I will do that, but first I need to be able to write and read the Displaywriter images, so far - one big FAIL.

So far I can only read/write DS/DD format:

Heads: 77
Sectors per track: 8
Sector size: 1024
Sides: 2
Data rate: 500K MFM

Low level format - PASS
Write - PASS
Read - PASS

Other formats tried, but failed:

DS/SD

Cylinders: 77
Sectors per track: 26
Sector size: 128
Sides: 2
Data rate: 250K FM

Low level format - PASS
Write - PASS
Read - FAIL, can read only first sector of each track

SS/SD

Cylinders: 77
Sectors per track: 15
Sector size: 256
Sides: 1
Data rate: 250K FM

Low level format: PASS
Write : PASS
Read: FAIL, can read only first sector of each track

What even more puzzles me, is that SS/SD images of Displaywriter software seem to be written with 500K instead of 250 - I have to use translation to 250 in ImageDisk settings to be able to write the image, but still - it fails with the same problem - can read only first sector of each track.

Could anyone help me with this issue? It seems I am stuck right there...

many PC floppy controllers cannot reliably write single-density format.
there is a test program on Dave's Imagedisk site which can be used to verify if your controller can write SD

8" disks always write at 500K
 

Chuck(G)

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What Al says is correct--don't confuse the clock rate with the bitrate. All 8" diskettes are written at 500KHz clock (high density), whether they're FM or MFM (or MMFM, but that's a different subject). The bitrate of FM is half that of MFM, but the clock is the same.

What are you using for a floppy controller? Has it passed the FM test of TestFDC{/url]?
 

MikeS

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What Al says is correct--don't confuse the clock rate with the bitrate. All 8" diskettes are written at 500KHz clock (high density), whether they're FM or MFM (or MMFM, but that's a different subject). The bitrate of FM is half that of MFM, but the clock is the same.
So, you're saying that the "data rate" in the OP's settings (which is what I think we're talking about) means "clock rate" and not "bit rate" and he should select 500K regardless of density?
 

MikeS

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Very likely yes, but I don't have his program, so it's hard to say for sure. But that's the usual convention.
Kind of counter-intuitive; I'd think "data" would refer to bits and not the clock, sort of like "baud" and "bps" in the modem world...

Clock rate and/or transfer rate would certainly make it a little less ambiguous.

Learn something new every day.
 
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