Soft Sector Controller

Discuss construction, troubleshooting, and operation of the Altair 8800c computer

Soft Sector Controller

Postby AltairClone » July 25th, 2021, 4:56 pm

I’m toying with the idea of adding two new drive types to the Altair FDC+. Operation of the Pertec FD3712 and its S-100 interface board could be duplicated with the FDC+ and 8” drives like the Shugart SA-800. This would allow support of the IBM standard SSSD 8” soft sector format on your Altair. Likewise, operation of the FD3812 and its interface board could be duplicated to provide support of the IBM System 34 double density format.

Existing FD3712 and FD3812 software (e.g., CP/M) could be run with these new drive types if the FDC+ is strapped to the I/O address used with the FD3x12 (C0h). Unfortunately, selecting this address would require a couple of minor board cuts/jumpers to the FDC+. Alternatively, a couple of minor patches to software would allow existing FD3x12 software to use the default address of the FDC+ (08h) instead.

Thoughts?

Mike
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Re: Soft Sector Controller

Postby toml_12953 » July 26th, 2021, 12:37 am

AltairClone wrote:I’m toying with the idea of adding two new drive types to the Altair FDC+. Operation of the Pertec FD3712 and its S-100 interface board could be duplicated with the FDC+ and 8” drives like the Shugart SA-800. This would allow support of the IBM standard SSSD 8” soft sector format on your Altair. Likewise, operation of the FD3812 and its interface board could be duplicated to provide support of the IBM System 34 double density format.

Existing FD3712 and FD3812 software (e.g., CP/M) could be run with these new drive types if the FDC+ is strapped to the I/O address used with the FD3x12 (C0h). Unfortunately, selecting this address would require a couple of minor board cuts/jumpers to the FDC+. Alternatively, a couple of minor patches to software would allow existing FD3x12 software to use the default address of the FDC+ (08h) instead.

Thoughts?

Mike


If you could have a DIP switch select the I/O address, that would be ideal.
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Re: Soft Sector Controller

Postby AltairClone » July 26th, 2021, 1:43 pm

toml_12953 wrote:If you could have a DIP switch select the I/O address, that would be ideal.


Hmmm, just make everyone who wants to try this feature buy a new board? Personally, I'd prefer the no-cost way of doing it :)

Mike
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Re: Soft Sector Controller

Postby toml_12953 » July 27th, 2021, 2:38 am

AltairClone wrote:
toml_12953 wrote:If you could have a DIP switch select the I/O address, that would be ideal.


Hmmm, just make everyone who wants to try this feature buy a new board? Personally, I'd prefer the no-cost way of doing it :)

Mike


No one would need to buy a new board since trace cutting and software modification would still be available for anyone not buying one.
However, changing the software seems to defeat the purpose of using the standard formats.

For new users or those of us who switch configurations regularly, a DIP would be a great way not to have to buy a second board to modify and
swap boards when we wanted to run the soft sectored disks. Either way, I'll be buying a second board but the physical swap will be hard on the connectors.
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