idea for a universal disk interface

[Paul Koning]

> On Apr 13, 2022, at 5:27 PM, Fred Cisin via cctech <cctech at classiccmp.org> wrote:
> 
> On Wed, 13 Apr 2022, shadoooo via cctech wrote:
>> The main board should include a large enough array of bidirectional transceivers, possibly with variable voltage, to support as much interfaces as possible, namely at least Shugart floppy, ST506 MFM/RLL, ESDI, SMD, IDE, SCSI1, DEC DSSI, DEC RX01/02, DG6030, and so on, to give a starting point.
> 
> Hmmm. rather than re-inventing the wheel, as we usually do, . . .
> 
> It may be possible to accomplish a subset of those, specifically including Shugart floppy, ST506/412 MFM, RLL, ESDI, IDE, SASI, SCSI by repurposing certain commercial hardware.
> 
> You would have a collection of boards, that you would remove/insert into a connector.
> 
> The main board would have RAM, and a ROM for certain basic (and BASIC?) functions, but would load software for various modules and output results to and from one or more interfaces that remain connected.
> 
> I don't doubt that you could design a far better system, but there already exists a crude version, ready to implement!
> 
> It has a marginal power supply, and it has a poorly designed group of 8 62 pin connectors for the interfaces, although some of those would need to be dedicated for other functions of the device, including user interface hardware.  Some software is already available, but some crude tools are available for creating more.
> 
> It says "IBM", "5160" on the back panel label, although there were plenty of generic second sources.
> The updated "5170" version of it could be more easily set up even for USB.

:-)

But the main goal that was mentioned is device emulation, which existing products generally don't do.  I see the idea as a generalized form of David Gesswein's MFM emulator, which is primarily a device emulator but is also capable of reading and writing devices to capture everything that's on them.

The puzzle is how to make it do, say, 2311 emulation suitable to talk to an IBM/360, 1311 emulation for the decimal IBM 1620, or 844 emulation for a CDC 6600 -- to mention just a few of the more exotic cases.

	paul