PC floppy cable twists...

[Jules Richardson]

... discussion about this on another list got me curious - what *was* 
the point of that cable twist in a (IBM clone) PC floppy cable, when 
every other system on the planet was using straight-through cables?

1) Great, it means both drives in a system can be jumpered for the same 
ID - but someone's still got to go in and jumper/modify the last drive 
in the chain so that it's terminated, so it's not like the twist 
eliminates messing around with jumpers.

2) when the twist was introduced, there were presumably no clone 
machines around (it was there from day 1 IIRC) - and wouldn't the 
addition of a second floppy drive to an IBM machine have been a field 
service call anyway? So it's not like it was the general public changing 
jumpers, but a trained engineer...

3) IBM seemed to use a very small range of drives in the PC / XT / 286 
days, so it's not like there'd be a million jumper combinations to 
figure out. If a customer tried to add their own drive rather than 
buying through IBM, surely IBM couldn't care less if they struggled to 
figure the drive jumpers on their 'non-standard' unit out?

It's got me curious as it seems like a hack that doesn't completely 
solve any kind of problem whilst introducing a difference between IBM 
and the rest of the industry.

cheers

Jules