On 1/10/19 10:30 PM, Jim Brain wrote: > On 1/10/2019 2:11 PM, Gerrit Heitsch wrote: >> On 1/10/19 5:35 PM, Mike Stein wrote: >>> I definitely don't want to revive/continue the floppy cable argument, >>> but I'm really curious whether there is another way. >>> >>> It's 1980, you're an IBM engineer in Boca Raton and your boss comes >>> over to your desk, drops a pair of Tandon TM-100s on it and says, >>> "I've got a challenge for you: we need a way to individually control >>> the drive motors on these drives without modifying the drives; can >>> you do it?" >>> >>> What would you do/say? >> >> The first question would be 'Why do you think you need to do that?' >> Quite often people who ask for a certain feature don't have all the >> facts or started from the wrong premises. >> >> Gerrit >> >> >> > Not that it matters, but you're just stalling... > > Others have already noted, and Internet resources agree, the decision > was made to minimize assembly complexity. No need to worry about drive > affinity on the assembly floor. > > Thus, the decision has been made, no jumpering on drives. How would one > address the situation? Well, if you want to have identical drives but be able to adress them seperatly and use a 34pin Shugart cable, then you have 2 choices: 1) Modify the cable between the 2 drives. Advantage: Only one cable necessary. Disadvantage: Special cable needed. Probably involved manual labour at least at the beginning => price. 2) Each drive gets its own cable to the controller card and the pinout of the 2 connectors on the card decides which drive is which. Advantage: Simple 1:1 cable. Disadvantage: You need one cable per drive. Option 1) also assumes you can have more than one DS line active at the same time. That is not necessarily a given with existing designs. GerritReceived on 2019-01-10 23:02:08
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