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IBM 5110 initial info

Does anyone remember the S/360 standard colors? I mostly saw "salmon" and whatever the blue one was (there was a darkish blue and then a baby blue) and I think there was a green.
This was a big thing back then--the old IBM mainframes (e.g. 7090) were gray--your only color choice.
 
Yabut the shells for the S/360 could be had in a wide range of colors that you wouldn't normally think suitable. But then, this was the 1960s. Yellow, orange, blue...
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Never understood the revival of mid-century modern...
Regardless of the colors, sure looks like a nice platform for a snooze.
 
Regardless of the colors, sure looks like a nice platform for a snooze.
That didn't die with the 60s. I recall visiting the new ETA digs in St. Paul in the early 80s. Brightly painted exposed pipes in the ceiling, office furniture done in bright primaries. Looked very anachronistic to this guy.
 
I was reading thru the IBM 5100 MIM, and I came across this: "RPQ"

There is a note that references "RPQ" in relation to MAP 950 - but going to MAP 950, it's just a blank reference with no elaboration.

Based on the footnote below, "RPQ" is just referring to a 2nd external tape unit. But, "RPQ" or the ability to use a 2nd tape unit isn't mentioned in the IBM 5110 MIM.


Hadn't seen two external tapes as a valid 5100 configuration, and was wondering if the letters "RPQ" meant anything to anyone (aside from some price quote!! :) )



From the IBM 5100 MIM (3-12):

1669617803126.png
 
Note that the ASCII Communications is listed as RPQ as well. I think that if the system had any devices ordered as an RPQ, those would have been supplied along with a maintenance manual update with troubleshooting information labeled MAP 950.

RPQ while it officially stands for "Request Price Quotation" is really IBM speak for more exotic options that require some changing to the rest of the system. For a second tape drive, the BASIC and APL would need to be informed that 20 is a legal device number. The tape drive would also need to be modified to respond to the different drive number. (According to online searches, there is a page with "(E20, E40, and ES0)" which might explain more. Note I think the last is a mis-OCR for E80. I can't find that snippet in the PDF I have. No fair that Google can read the OCR from Bitsavers but my local PDF reader can't.)

One interesting point is that the internal and external tape drives could be swapped on the 5110 and it might even be possible to have only an external tape drive which is referred to as internal. See page 4-117 of the 5110 MIM.
You can swap either the parts of the tape units (internal
and auxiliary) or the complete tape units (physically or
electrically). To swap electrically, swap the cable in the
Z2 socket of the 5110 A 1 board with the cable socket
in socket B4 of the Auxiliary Tape Unit. The internal
tape unit address is now E40 (BASIC) or 002 (APL).

I didn't see this reference on prices in earlier pages but it explains why users of the 5110 were happy to lose the tape drive. Internal tape drive was a $1400 option; external cost $1850. http://oldcomputers.net/ibm5110.html
 
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Ah, so it is a custom price quote after all - yes, I think you're right.

And that would make sense (there is also the footnote in the MIM where IBM says you can only have two IO devices -- and most people would probably want 1 external tape and 1 printer, so that's the configuration they focused on).



I recently did swap an IBM 5106 external tape unit into an IBM 5110 Type 1 that had a "not-working" internal tape unit. That went fine. It turns out that not all IBM 5106 external tape units are compatible with the 5110. The manual mentions some jumpers changes on the 5106 tape adapter (to make it compatible between the 5100 and 5110), but apparently the early builds of the 5106 don't have those jumpers. So, I'm very curious what those jumpers actually did - maybe slight timing adjustments between the 5100 and 5110? Actually, I see the 5110 SLM Auxiliary Tape Adapter and the 5100 MIM section 5-50 Auxiliary Tape Adapter, maybe I can spot some schematic difference there that might be a clue.


Oh - in the 5100 MIM pg5-51, there is a description in the lower left that suggest you could actually have up to 7 external tape. Or, at least the subaddress device has up to 7 options.

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Does anyone know the cost of QIC tapes "back in the day" (mid 1970s)? I can't even recall the early days of 5.25" disk anymore (in terms of price) - maybe $5/disk? But where would you even get a QIC 3M tape back then? (not the local drugstore - probably in '75 it was an order from your IBM rep?)


Speaking of QIC tapes... The 5100 docs give some spec of about 207KB on a tape. That's a DC300 or DC600? But the more modern DC6150s have much more capacity, right? i.e. the 207KB isn't really a system limitation, but was a limitation on the amount of actual tape media? (actually, the QIC tape header spec indicates a file limit of 32K files and 16K per file max, per the format spec - I'm not sure how many feet that 512MB would translate to, but maybe more than what the standard QIC reels could fit?).
 
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I remember new DC300 and DC600 tapes being priced at about $20 each. Even in 1988, Micro Cornucopia magazine had an ad offering used DC300XL tapes for $5. QIC tapes were relatively common since many other companies used them like Tektronix.

IBM used DC300 since the longer tapes hadn't been invented yet. ~200K was partly caused by the length of the tape and longer tapes would store proportionally more. Later QIC drives changed the read/write heads to store more. Xitan offered 13MB on a DC300 cartridge in 1981.
 
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