On 2023-08-12 22:30, Fred Cisin via cctalk wrote:
Could y'all clarify for me,
Do you mean "drive 3" and "drive 4" of drives 1-4, or 0-3?
do you mean "DS2" and "DS3" of DS0-DS3, or DS1-DS4?
On Sat, 12 Aug 2023, Nigel Johnson Ham via cctalk wrote:
As far as i know, winchester drive selects have always been 1-4, at
least in the DEC world!
Reference MP-02259-01 RQDX3 Field Maintenance print set. Also
Plessey DCV54 manual.
I don't know about PCs- I went into teaching when the PC came out
'cos there wasn't enough money in PCs! I was getting $90 and hour
in the DEC world and people were working for $20-30 in the PC world :-(
Nigel
Thank you!
I wasn't in the DEC world, so I appreciate your taaking the time to
tell me.
I did much more work with varying types of floppy drives, and not so
much hard drives.
Floppy drives are commonly called DS0 - DS2, with a few exceptions.
https://old.pinouts.ru/HD/InternalDisk_pinout.shtml
http://www.interfacebus.com/PC_Floppy_Drive_PinOut.html
But, the Shugart SA400 OEM manual calls them DS1-DS3
https://deramp.com/downloads/floppy_drives/shugart/SA400%20OEM%20Manual.pdf
http://www.bitsavers.org/pdf/shugart/SA4xx/SA455_SA465_Service.pdf
https://deramp.com/downloads/floppy_drives/shugart/SA800%20OEM%20Manual.pdf
And the Teac Specifiation calls them DS0-DS3
http://www.bitsavers.org/pdf/teac/FD-235HF-A529_A540_A591_Specification_Rev_B.pdf
https://deramp.com/downloads/floppy_drives/teac/TEAC%20FD-55GFR.pdf
Just to keep it confusing, PC jumpers all floppy drives on the second
position, pin 12 of the SA400 pinout (DS1 of 0-3 or DS2 of 1-4), and
then selects by the cable.
TRS80 set all floppy drive select jumpers ON, and used a cable with
only one of the drive select lines present in the drive connector, to
also select by the cable.
Fourth drive (DS3/DS4) had some complications, as some systems
re-defined that pin of the cable for other uses.
But, I located the Seagate ST506/412 OEM manual
https://minuszerodegrees.net/manuals/Seagate/Seagate%20ST506%20ST412%20-%20OEM%20Manual.pdf
and, as you said, the drive selects are shown as DS1-DS4.
Wikipedia, however, calls them "DRV SLCT 0" - "DRV SLCT 3"
in its diagram of pinout
https://en.wikipedia.org/wiki/ST506/ST412
https://en.wikipedia.org/wiki/ST506/ST412#Connector_pinouts
--
Grumpy Ol' Fred [email protected]
You've amplified my point, Fred! When I saw the abomination of
cross-over selects in the cables in the IBM PC, I knew the need for
Field Service Engineers was coming to an end!
I don't believe anything on Wikipedia anymore. When I saw them say that
there is no such thing as a legal definition for a pint of beer in
Canada, I got an actual legal definition from the Federal Government,
created an account on wikipedia, and put in the correct legal definition
with a reference to the law. (It's 568.26 ml btw - make sure you get
that last .26ml :-) )
I week later it had been changed back to the previous text, and I could
not get in to correct it!
Only when they asked me for money did I get to email an actual person to
complain!
cheers,
Nigel
--
Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
Skype: TILBURY2591
