Re: Commodore drives can be controlled on Apple II serial!

[Rubywand <rubywand@swbell.net>]

Supertimer writes ...
> 
> Apple II and PC have problems sharing disks because one uses
> GCR encoding and one uses MFM.  People want to share data
> downloaded on a PC with the Apple II.  What to do?  I have been
> asking some questions about the Commodore 1571 5.25" floppy
> drive on comp.sys.cbm and discovered that it is an intelligent
> serial device that can be controlled in ANY computer with the right
> driver.  This drive can read and write MFM encoded MS-DOS
> disks, besides GCR encoded Commodore disks.
> 
> Commodore drives are very plentiful.  They are at least as plentiful
> as Apple II 5.25" floppy drives.  They have their own 6502 brain
> and RAM.  The computers talk to them using an RS-232 serial
> connection and download the files from disk like they would from
> a modem.
>
> Can a driver be written for the GS to control these serial MFM disk
> drives?

     If, as you say later, the C64 drives can be run from a PC COM port,
there should be no problem running the drive from a GS serial port.
Given information about which signals and codes the C64 drive needs, an
interface routine could be probably be written.



> This would make sharing data on 5.25" disks with a PC a
> snap.  More importantly, can a ProDOS 8 program be written to
> read and write data from a Commodore 1571 disk drive connected
> to a Super Serial Card?  Apple IIe and IIc users can then transfer
> data from their PC units to their hearts' content.  Disk transfer is
> much faster than null-modem or modem transfer, right? ....
>

     That is not altogether clear. C64 disk I/O is not especially
speedy. I just transferred a 178k file to our GS (PC HyperTerm to GS
Spectrum) at 56k baud. The transfer took about 35 seconds. Based upon
memories of long waits for C64 program loads, I'm pretty sure the C64
drive connected to a GS could not do much better.

     Diskette transfers are sometimes characterized as being especially
"convenient". Yet, the only inconvenience involved in the 178k transfer
was starting a couple telecom programs. The GS serial port is always
connected via a NULL modem connector to the PC's other COM port; so,
there is no need to mess with moving around cables. And, the PC can
handle the transfer as a background task; so, there is no need to wait,
exit your net connection, etc..

     Another consideration is file size. Many .SHK files and Jpegs are
too large for 5.25" diskette. (Some are too large for 3.5" diskette.)
Transfer via diskette would be pretty cumbersome for large files.


> 
> If you think I am crazy, you should know that there are two DOS
> programs that can run Commodore serial disk drives from PC
> COM ports.

     Although NULL modem still looks like a better way to do GS-PC
transfers, connecting a C64 drive may be a good approach for IIe users.
Besides, it's a fun idea. Maybe the DOS programs would supply the
information needed to come up with a IIe or GS version.



Rubywand