Differences between HP-9114A and 9114B


What is the difference between HP-9114A and 9114B ? Can anyone tell me ? Thanks


I could be way wrong, but when I used these drives about 100 years ago :-)....

I seem to recall that the 9114A was a single sided version of the 9114B. The differences then are that one has twice the capacity of the other.

The 9114A's I saw were rather more primitive inside than the 9144B's. but that may have had a lot to do with the fact that the 9114A's I saw were _VERY_ early production models. Many (all?) of the HPIB drives went through several revisions, sometimes changing the height of the case without changing model numbers.


I have one of each. The 9114B is cosmetically identical to the "A" model, and the only observable software difference is that it responds to the "ID" command with the different model number. Internally, you can see that the electronics of the "B" model is somewhat simplified. I have read (though not verified with personal experience) that the "B" model uses less power, and thus should have a longer battery life when in use. I have a manual for my "A" model which gives predicted battery lifetimes, so if someone has a "B" model manual, we could compare the figures.

Note that both models use _only_ the old single sided diskettes, and have identical formatted capacity.



Then what am I thinking of?

The early HP150 dual disk drive part number (something very like) 9114 (???).

I don't have any of these any more, but I do have the floppy that came out of one...


I don't know what you are thinking of ... But I have one 'A' and 2 'B' models and they are *not* cosmetically identical. The front panels are different with the B having 3 or 4 lights (can't remember) to indicate battery condition and the A having only a single power light. Also the B works with double sided disks (although I have no idea whether it actually uses both sides) but you have to tape up the slot opposite the write protect tab to get the model A to work with double sided disks.

Marwan Joury


Both my "A" and "B" models have the same number of LED battery indicators. The only difference on the front panel is the model number. It sounds like your "A" might be an earlier revision, or a prototype.



Hi Grant,

Does your 'A' unit handle double sided disks or do you have to tape up the slot opposite the write protect tab to get it to read them?


Marwan Joury


After a bit of research I believe I was referring to the 9122 drive, not the 9114.


The HP 150 uses a HP-IB interface not HP-IL. It probably had a HP 9121 or 9122 disk drive. The later 150s used a 9123. You could get a HP-IL interface for the 150 and put a 9114 on it but it's a kludge.


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