My Osborne 1 has a rev F main board, bios rom 1.44 along with both the DD daughter card and the Screen Pak upgrade. I also have a GoTek as drive B that I boot to (swaps A and B). When I use "Copy" version 3.1 to format a floppy disk it does not ask me if I want to format single or double density, it just starts formatting an every sector shows an "E". I can't find any newer version of COPY than version 3.1. Is this the correct version of COPY? I seem to be able to read SSDD on the GoTec just fine but have never gotten either real floppy drive to format a disk. Both real floppy drives are spinning at the correct RPM and are able to move the head.
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can't format floppy disk on Osborne 1
- Thread starter Lemonhawk
- Start date
cj7hawk
Veteran Member
Dirty head would be the first thought, and faulty FDD would be the second. It can also be the quality of disk ( eg, HD disk in DD drive ) or even just a change in disk coercivity ( Try degaussing the disk in advance ).
johnx993
Veteran Member
And a big question is... did it work before? When did it work and when did it stop, and did you do anything to the machine in between?
Or has it never worked? And yes, there are multiple versions of COPY. Ensure you are using the one for DD, and of course ensure you have a DD drive.
And can you read a floppy, as opposed to formatting it?
Or has it never worked? And yes, there are multiple versions of COPY. Ensure you are using the one for DD, and of course ensure you have a DD drive.
And can you read a floppy, as opposed to formatting it?
daver2
10k Member
Yes, many of the faults that can affect formatting a disk, should also affect writing to a disk...
Dave
Dave
The Osborne 1 was working when I retired it in probably 1985. I'm trying to resurrect it. Just replacing 2 ?rifa? caps in the power supply (I was expecting , but the 3rd one was a ceramic disk cap) and a doxit allowed the computer to boot, but I had no floppy disks. So I installed a GoTek emulator in the drive b slot. That allowed me to boot up CPM, but could not format an actual floppy disk - the copy format only produced "E"'s. The computer then failed and I fixed so its now back to no being able to format. Neither floppy disk drive will format. I did replace UA19 but this did not fix the formatting issue. I have no problems reading disks that are on the GoTek floppy emulator. Also, COPY does not ask if I want to format the disk as single density or Double Density, it just goes right to trying to format the disk, The video that I watched that had this problem was why I replaced UA19 a 74LS244, but it did not solve my unable to format issue. My COPY version is 3.1, Boot ROM is 1.44 and I have the DD daughter board an the Screen Pak all installed. So far all I find is version 3.1.
daver2
10k Member
Bit you haven't answered the question that was asked: Can you write to the GoTek for example?
If not, it is the write side of the controller that is faulty in some way, and that should be easier to find.
Reading (from the GoTek) clearly works if you can boot CP/M. But this doesn't test the write capability.
Dave
If not, it is the write side of the controller that is faulty in some way, and that should be easier to find.
Reading (from the GoTek) clearly works if you can boot CP/M. But this doesn't test the write capability.
Dave
Writing to the GoTec Sounds like a good test. I'm just not sure how to actually do that. Seems like I need the CPM system disk in order to bring up copy or pip. Maybe I can then switch to the blank disk and try to make a directory? Its only be 40 some years since I used CPM so its a bit hazy
daver2
10k Member
What have you got on the GoTek boot disk?
Dave
Dave
I used "COPY" and formatted the "BLANK" disk on the GoTek. After about 5 tries and getting 2 or 3 "E" it actually formatted the BLANK disk in the GoTek! Also when formating the GoTek it always asked about formatting it either Single or Double density, something is does not do when trying to format on the real floppy drive. I always chose Double.
daver2
10k Member
That is good.
I was going to suggest using the SAVE command (that is built in to CP/M). This command saves blocks of 256 bytes to a named file. For example:
SAVE 4 DER.BIN
Should save 4 blocks of 256 bytes (a total of 1024 bytes) from address 100h to a file called DER.BIN.
The fact that it is a little hesitant when you did your COPY does indicate a problem somewhere.
This is another data point for us!
Let me think a bit more...
Dave
I was going to suggest using the SAVE command (that is built in to CP/M). This command saves blocks of 256 bytes to a named file. For example:
SAVE 4 DER.BIN
Should save 4 blocks of 256 bytes (a total of 1024 bytes) from address 100h to a file called DER.BIN.
The fact that it is a little hesitant when you did your COPY does indicate a problem somewhere.
This is another data point for us!
Let me think a bit more...
Dave
daver2
10k Member
That is a data bus buffer. Unlikely (in my opinion) to be that.
Are you able to copy COM programs on to your GoTek to run?
We could do with a simple test program...
The disk controller is probably telling us what the error is, it is just that COPY is not being helpful and reporting it to us...
I agree that it could be timing, or an intermittent signal between the controller and the drives (including the GoTek).
Dave
Are you able to copy COM programs on to your GoTek to run?
We could do with a simple test program...
The disk controller is probably telling us what the error is, it is just that COPY is not being helpful and reporting it to us...
I agree that it could be timing, or an intermittent signal between the controller and the drives (including the GoTek).
Dave
daver2
10k Member
Just thinking aloud... Termination resistors...
Can you draw out a very rough sketch of the cabling between the disk controller and the disk drives, specifically identifying which drive(s) contains the termination resistors.
Only ONE drive should have termination resistors and this should be the drive 'furthest away' from the disk controller.
The terminator resistor package is RN3 and should be on the left hand drive assembly. Check to see whether the GoTek has / does not have terminator resistors.
Dave
Can you draw out a very rough sketch of the cabling between the disk controller and the disk drives, specifically identifying which drive(s) contains the termination resistors.
Only ONE drive should have termination resistors and this should be the drive 'furthest away' from the disk controller.
The terminator resistor package is RN3 and should be on the left hand drive assembly. Check to see whether the GoTek has / does not have terminator resistors.
Dave
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The Osborne disk cable goes from the MB to drive B, which is where the GoTek is then on to drive A where the termination resistors are. I have to move them if I put the floppy disk in. The reason for replacing UA19 the 74LS244 is in an video, the person mention that historically he has had problems with 244's being a little slow, and replacing it caused the copy program to then ask if you wanted to format SD or DD and fixed his formatting problem. I have a T48 that will test ic and program proms , but its unlikely that its checking timing. I do have a 244's from a different manufacture so I'll give that a shot since I already have a socket at UA19. I'll also check to see if there is some sort of difference between SD and DD floppies that can be checked by the controller without running the motor. The GoTek is loaded with all the Osborne diagnostic disks, but virtually all the disk diagnostics want to start with a formatted disk.
daver2
10k Member
Does the GoTec have termination resistors accidentally fitted, or is it a switchable termination configuration with the option turned ON by accident?
IC testers do not (in general) test timing. Nor do they test a whole load of other parameters either (e.g. voltage margins etc.).
UA19 buffers data between the DRAM and the data bus, so no direct connection between the disk subsystem and UA19. A slow buffer could, however, corrupt the data bus - and this may appear as a disk issue. But I would have expected this type of fault to manifest itself elsewhere also.
Dave
IC testers do not (in general) test timing. Nor do they test a whole load of other parameters either (e.g. voltage margins etc.).
UA19 buffers data between the DRAM and the data bus, so no direct connection between the disk subsystem and UA19. A slow buffer could, however, corrupt the data bus - and this may appear as a disk issue. But I would have expected this type of fault to manifest itself elsewhere also.
Dave
Last edited:
MicroCoreLabs
Veteran Member
- Joined
- Feb 12, 2016
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Have you tried to format using FORMAT and copy using PIP?
daver2
10k Member
As far as I can tell, the data lines run everywhere. So any faulty IC that is connected to the data bus could (in theory) corrupt one (or more) data bits. This should (however) not be just related to the disk controller.
Can you check to see if jumper J3 is fitted. This connects the disk controller DDEN pin 37 (Double DENsity) to the controlling logic (UC15 pin 2 PA0) so that the density pin can be driven. To my knowledge, the density operation has to be a function of the disk drive itself and the Osborne 1 logic - and not the disk controller. The disk controller is told what density it is supposed to be operating as by the operational firmware/software. The density is usually determined by a notch and sensor in the drive mechanism/electronics driving the logic. Alternatively, it could be wholly defined by firmware/software within the Osborne 1. It can also be determined from the disk formatting itself. But this now poses a problem if the disk is completely blank, as the formatting is not defined...
The disk controller IC data sheet can be read here: file:///C:/Users/ed01415/Downloads/WD179X.PDF. The FORMAT commend will use a Type III WRITE TRACK command. You can follow the flow chart for this command from the data sheet. When the command completes, the disk controller status register will hold any errors that occurred - identifying what it was unhappy about. The question is how to read this status register and report it?
The head is stepped on via a TYPE I command. Is it possible this is erroring rather than the WRITE TRACK.
Ah, page 185/589 of https://bitsavers.org/pdf/osborne/osborne1/2F00153-01_Osborne1TechnicalManual_1982.pdf gives us some clues. There is a ROM monitor. I wonder what this can do for us, and how to enter it? More reading required...
Dave
Can you check to see if jumper J3 is fitted. This connects the disk controller DDEN pin 37 (Double DENsity) to the controlling logic (UC15 pin 2 PA0) so that the density pin can be driven. To my knowledge, the density operation has to be a function of the disk drive itself and the Osborne 1 logic - and not the disk controller. The disk controller is told what density it is supposed to be operating as by the operational firmware/software. The density is usually determined by a notch and sensor in the drive mechanism/electronics driving the logic. Alternatively, it could be wholly defined by firmware/software within the Osborne 1. It can also be determined from the disk formatting itself. But this now poses a problem if the disk is completely blank, as the formatting is not defined...
The disk controller IC data sheet can be read here: file:///C:/Users/ed01415/Downloads/WD179X.PDF. The FORMAT commend will use a Type III WRITE TRACK command. You can follow the flow chart for this command from the data sheet. When the command completes, the disk controller status register will hold any errors that occurred - identifying what it was unhappy about. The question is how to read this status register and report it?
The head is stepped on via a TYPE I command. Is it possible this is erroring rather than the WRITE TRACK.
Ah, page 185/589 of https://bitsavers.org/pdf/osborne/osborne1/2F00153-01_Osborne1TechnicalManual_1982.pdf gives us some clues. There is a ROM monitor. I wonder what this can do for us, and how to enter it? More reading required...
Dave
daver2
10k Member
It looks like the ROM requires to be Version 1.3 to support double density. The ROM firmware version should be output when the machine is powered on (or reset) and is waiting for a disk to be inserted.
As far as I can tell, the ROM only covers booting from a disk drive ( A: or B: ) as part of the reset process.
The default is to check the density (including the sector size and number of sectors per track) from a valid read of the disk. If the disk is BLANK, then there may be some lower-level detail within (for example) the FORMAT commend that permits the choice of single or double density?
My analysis of the firmware subroutines so far seems to imply that the disk controller status register value is pretty much destroyed in favour of fixed values (and/or the Carry flag setting).
I can't see any useful method of installing any test software - other than inserting a new ROM or relying on the fact that we can boot some software from the disk (bypassing CP/M). This presupposes that reading and the RAM itself works of course.
Dave
As far as I can tell, the ROM only covers booting from a disk drive ( A: or B: ) as part of the reset process.
The default is to check the density (including the sector size and number of sectors per track) from a valid read of the disk. If the disk is BLANK, then there may be some lower-level detail within (for example) the FORMAT commend that permits the choice of single or double density?
My analysis of the firmware subroutines so far seems to imply that the disk controller status register value is pretty much destroyed in favour of fixed values (and/or the Carry flag setting).
I can't see any useful method of installing any test software - other than inserting a new ROM or relying on the fact that we can boot some software from the disk (bypassing CP/M). This presupposes that reading and the RAM itself works of course.
Dave