Den Thu, 10 Jan 2019 16:03:00 -0600 skrev Jim Brain <brain@jbrain.com>: > On 1/10/2019 3:46 PM, Gerrit Heitsch wrote: > > > > 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. > > > I would concur. I can only thus assume that the cost to flip the > wires was less than the cost for the second set of wires, single IDC > conn (the other would be needed either way), and the 2 extra IDC > headers on the FDD card (to support 4 drives) outweighed the early > manual cost of flipping wires. Probably a safe assumption, given the > cost to lay out the 2 extra conns on the FDD controller would have > driven up cost quickly (PCB space, etc.) IBM actually used an edge connector on their first floppy controller. Not sure if there would had been room for two such connectors. (The 37-pin dsub for two external drives wouldn't had been a problem though as you'd anyway need special cables for that connector). BTW with two separate cables, you could run in to problems with bad signal quality on the read/write signals due to reflections. The only computer I know of that had two cables were the Ericsson PC. It had two really short cables with the motherboard connectors directly beneath the drive bay (with room for two 5.25" half height units, usually fitted with TEAC FD-55B). -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies.Received on 2019-01-11 01:00:03
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