>That DB25 SCSI port, for example (which IMHO doesn't have enough ground
>pins) rather than a 50 pin connector. Or those infernal Mac serial ports
>(I am not sure what they really are, they're not RS232, RS422 or RS423).
>Or the early Mac floppy drives -- I am thinking of things like the 800K
>DS drive. It's undoubtedly a clever design, but I wonder how many users
>would have prefered to be able to exchange floppies with people who used
>other types of computer, rather than being able to fit 10% more data on
>the disk. Or Nubus, which has a number of incompatibilities with 'real'
>Nubus.
You'll have to remember though that 720k/1.4meg 3-1/2" floppy
drives weren't common in the PC world until after IBM introduced the
PS/2 line. That's when the PC's jumped onto the 3-1/2"
bandwagon..after the Atari, Amiga, and Apple machines had been using
them for at least a couple of years. When both the original Mac and
the Lisa began using the Sony 400k 3-1/2" there wasn't a need to
consider making it compatible format-wise with anyone else because
they were some of the first machines to use the form-factor.
As for both the SCSI connector and the serial ports, the main
reason I can see for Apple doing it the way they did was due to space
constraints on the rear of the compact form-factor Mac's. There just
wasn't enough room physically to use the larger connectors and fit
everything they wanted to on the rear of the machine. Considering
the small size of the machine, there's an amazing amount of I/O
coming off the rear of the compact Mac's, especially the ones such as
the Color Classic that can even have a PDS card installed. Certainly
there weren't many machines outside of high-end servers and such
using SCSI in 1985 anyway. The Mac's, along with 3rd-party Zorro-II
boards for the Amiga 2000, were some of the first systems geared for
home use that utilized SCSI and both used the same DB25 connector.
Even the Amiga 3000 used the DB25 SCSI connector as did quite a few
early ISA SCSI boards.
Concerning the NUBUS design, other than the info I've seen
posted on this list concerning it's use in other machines, I don't
know enough about it to comment.
Jeff
--
Collector of Classic Microcomputers and Video Game Systems:
Home of the TRS-80 Model 2000 FAQ File
http://www.geocities.com/siliconvalley/lakes/6757
Received on Sat Mar 24 2001 - 19:28:46 GMT