Support unusual sector sizes

[wohali]

Symbolics Lisp machines require an unusual disk sector size: 1280 bytes.

Currently the firmware does not support this.

Can support be added for unusual sector sizes please? Otherwise, the device is not usable in these machines.

[connorwk]

FWIW I simply removed the if statement, compiled and threw it on my device and it works great now with 1280 byte blocks on the Symbolics XL1200 I have.
I was also able to modify an image file from a SCSI2SD which rounds its stored blocks to the nearest 512bytes, so it was 1536 bytes per block with a padded 256 bytes at the end. Removed the padding for every block and it works great on the zuluscsi now.

An if statement blocking support for certain block sizes when the code seems to support it no issue seems counterintuitive.
If you're going to have a supported list at-least having it documented would be handy.
Maybe just throw a loud warning in the log if you see a block size your not expecting to help point folks in the right direction.

Another point brought up while discussing this with others are block sizes like 520 byte block sizes, used by IBM.

[aperezbios]

@wohali here's a build for you to test whenever you have some time
ZuluSCSI-firmware-arbitrary-block-sizes-test.zip

[wohali]

Thanks @aperezbios this looks to resolve the issue.