Originally posted by BillDowns:
</font><blockquote>quote:</font><hr />Originally posted by RainOfSteel:
</font><blockquote>quote:</font><hr />Originally posted by BillDowns:
An IBM 3083 central unit of the late 70's cost [...]
Worked on one!
In 1994, no less. </font>[/QUOTE]Big Sicker, wasn't it
Mainframe-wise, I've worked on a militarized version of a Univac 1108, on IBM 4341, 4361, 4381, 3083, 9612, and 9672 mainframes. I would love to work on a z370. (how do you out in a drool??) </font>[/QUOTE]The 3083 (4 CPU) was rolled out about four month after I arrived and was replaced by a 3084.
The 3084 (3 CPU) lasted from around Nov-1994 to approx. Jun-1996, when it replaced with, I believe, a 9672 (2 CPU). That was there until I left in 1999.
We lost a CPU with each move, but gained tremendous horsepower.
The move from the 3083 to the 3084 required an entire team of 16+ individuals who tiger-teams the job in 36 hours. Some were coolant techs who came in, pulled up the floor panels, and repiped the cooling system.
They were putting the main cabinets together when they suddenly discovered that the main "grouper" cables (high speed data transmission for communication between CPUs in different cabinets) were not present. They had to do counter-to-counter airline delivery shipping to get a pair from that mainframe's original location (they'd been left behind on accident).
IIRC, the set up was like this (ASCII art to follow):
Note: Each # is a the size of a 7 foot high large fridge.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"># | #########
#
# | #########
----- -------
#
##
##
# ###
# ###
##### #
#
##### #
#####
#####
##</pre>[/QUOTE]The top vetical set of 3 symbols were the cooling pump.
The top two horizontal sets of 9 symbols were the uniterruptable power supply (UPS).
The rows of hyphens and vertical lines represent walls, as the top two sets of equipment were in different rooms. The pumps made a huge amount of noise (thunderous).
The odd offset cross-shape below the UPS was the mainframe.
The lone symbol was the master start-up CPU that controlled mainframe bootup and shutdown.
The two horizontal sets of 3 symbols were the power conditioners, they were there to produce absolutely smooth electrical power for the mainframe. (Think of them as gigantic and spiffy power supplies.)
The bottom four horizontal rows of symbols were DASD (Direct Access Storage Device) strings. Each was filled with harddrives, and each hard drive was the size of a suitcase and weighed 70 lbs. I should know, when a service tech showed up to replace one, he had to coopt me to help him lift the old one out and the new one in (it wasn't that 70 lbs. was too heavy, it was that they were awkward and placed oddly in the cabinets). I believe each HD unit had a capacity of 250/350 MB, or something like that (I can't remember for sure).
The vertical set of three symbols next to the DASD strings was the DASD controller.
The bottom two symblos were the . . . hold on to your socks . . . reel to reel tape drives. Used in multiple daily operations, no less. Including for transfers to a Unix server (that had a speciallized SCSI reel tape drive on a flat bed mounted in a rack next to the servers). When asked why they just weren't ethernetted/token-ringed together, the response was, "Do you have any idea how expensive that peripheral is for a mainframe," or, "The mainframe is just too old." Both were untrue, and I always laughed my rear end off, privately, of course.
The mainframe was connected to the DASD controller by 36 speciallized cabled, each about one inch thick and typically, I think, about 10-15 yards long with giant hand-sized plugs at each end.
The mainframe also had 36 extra computers called "channels" (on top of the 3 main CPUs). Each channel computer CPU ran communication requests from the mainframe to storage over one of 36 cables connected to the DASD cable (at the time, 4MB/sec. was each cables' max speed).
This gave the system an aggregate transfer capacity of 144MB/sec. That was quite a bit back in 1994.
It also wasn't a "hypothetical" maximum, where you didn't actually achieve that limit (like ethernet or modem "so-called" maximum speeds). You actually got that transfer rate.
Because there were 36 extra computers asynchronously handling all I/O requests, the 3 main CPUs were left to do real work.
That mainframe, small and limited as it was for the breed (the 3084 could be expanded quite a bit over what we had), was extremely powerful. It could handle 500 concurrent users plus continually executing batch jobs.
Oh, and I think I missed out discussing one, and possible two cabinets and their functions. (I'm thinking there may have been a cabinet that received the underfloor cooling pipes, and then redistributed them.)