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Early Computer Hardware

With the abacus-shaped item below, I have finished off my collection of first generation computer miscellanea.  The device may not look like much, but it is a pretty hot collectable among a peculiar bunch of people.  It is a module from an IBM 700 series mainframe computer.  These, and ferrite memory planes are among the most collectable pieces of early computer hardware.

IBM was proud enough of the unique abacus look of these modules that they were featured in a 1953 ad for the new 701 computer.

Here is the module featured again as “the old-timer” in a comparison with state of the art computer chips in 1975.  Note the T-shaped tool for removing the unit from its socket.

As you can imagine, there are not a lot of these modules around, and they get snatched up anytime someone finds a box of them at an electronics salvage house or a barn. 

Not too often that you find top tier computer hardware pieced together with cloth wiring!  This is truly first generation computing.  First generation machines are tube.  Second generation are discrete transistors (very early 60’s).  Third generation use integrated circuits, while forth generation use large scale integrated circuits.

I remember an old-timer at my college talked about a tube-type computer they had at Louisiana Tech in the early 1960s.  He said it would get slightly different answers depending on the temperature and relative humidity!

The computer this module came from looked like the pictures below (think–heavy metal).  The first three are IBM 704 machines from around 1954.  The forth picture is Ronald Regan eyeing an IBM 701.  Note the mass of hand soldered wiring in the third picture.  The 701 was introduced in response to the Korean War, and marketed to the government as a tool for use in airplane design, munitions manufacturing, and nuclear development.  The 702 and 704 were aimed more at commercial and scientific users.  Google these IBM models to find these photos and excellent write-ups on these and other early machines.

As primitive as these tube modules seem, they were not the weak link of early computers.  The 701 and 702 line used CRT memory.  Dots were projected on the screen of TV picture tubes with special long persistence phosphor.  These dots were then read photovoltaicly as memory bits.  The machine and software had to be quick enough to retreive the bits from memory before they faded away!  This was far better than mercury acoustic delay line memory (pulsing mercury in a long tube, then reading the acoustic pulses at the other end of the tube).  Defiantly not random access memory.  

The 704 had the new, much improved ferrite magnetic core memory.  This new technology was high speed, instantly erasable, and most importantly–random access.   The 704 was also the first large, commercially available computer capable of floating point math.  

As you can imagine, tube computers ate lots of power and air conditioning.  A typical 704 had to be wired to a 105 kva power source, and cooled with over 21 tons of air conditioning.    

Some other mementos from first generation computing:  

Below are plug-in tube modules from a 1950’s Monroe computer.  These are new-old stock–never used.  Note the 1955 packing slip and the spring mounts for the bottom unit.  The small tube is a voltage regulator, also used in 1950’s Motorola color TVs to be sure the high voltage power supply didn’t run out of control.  An old computer engineer told me that these units represented one bit of information.  They are identical to modules found in the earlier, IBM 600 series computers as you can see from the ads below.

Can you imagine when the IT guy shows up with a briefcase full of tube modules?  (this case sold on EBay a while back)

More primitive forms of memory were replaced in the mid 1950’s with ferrite magnetic core memory.  Early versions of these memory planes were not made by machine, but were sown together by seamstresses.  So dress makers also made computer parts!   Here is 100 bits of memory.  The tiny ferrite donuts were magnetized in either a clockwise or counter-clockwise direction to represent a 1 or 0.  As such, they were also non-volatile memory. 

Now, something amazing.  Here is a 16K memory board from 1977.  See those black rectangles?  Keep looking closer–16,000 tiny ferrite donuts.

Here is a very early magnetic drum memory from the 1950’s .  This unit was not used for mass storage like a hard drive, but as non-random access memory.  Think access time of about one to two minutes to read the entire drum.  And you thought your computer was slow?

A tube-type digital counter with display:

Before hard drives, your computer program was stored on tape.  To run your program, you had to load your tape on the machine and find the program on the tape.  A Burroughs tape of electronics calculations from about 1963:

A programming board (yes, software) from a 1946 IBM pre-computer.  This very visual program ran the quarterly report for an electric company in Shreveport, Louisiana.  This machine was the refrigerator-sized equivalent of an Excel spreadsheet.  This programming board defined the equations.  Data was imported on punch-cards.  The machine then outputs the answers by punching more cards.  

See the programming board at the lower right?  No, I don’t own this boat anchor!

A programming schematic for developing your software!

So you thought your computer problems were tedious?  Our immediate technical ancestors had to wrestle answers from some pretty ungainly machines–yet they thought they had it easy compare to their predecessors!

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