Programmable Calculators: Texas Instruments SR-60

Texas Instruments SR-60

*Datasheet*	Years of production:	1977-1979	Display type:	Alphanumeric (matrix)
	New price:	USD 995.00	Display color:	Red
	·	·	Display technology:	LED
	Size:	14½"×17"×5½"	Display size:	20 characters
	Weight:	16 lbs	·	·
	·	·	Entry method:	Algebraic with precedence
	Batteries:	N/A	Advanced functions:	trg, exp, log, drg, dms, alpha, printer
	External power:	110-220V AC	Memory functions:	+/-/×/÷
	I/O:	I/O port, memory expansion port	·	·
	·	·	Programming model:	Unmerged keystroke, magnetic cards
	Precision:	12 digits	Program functions:	GOTO, cond, subr, labels, ind
	Memories:	40	Program display:	Mnemonic
	Program steps:	480	Program editing:	SST, BST, overwrite, insert/delete

sr60.jpg (72232 bytes) Back in 1982, when I was a lowly conscript in the Hungarian People's (yeah, right) Army, I used to carry a beast just like this one under my arm. The story was simple: one of my superiors decided to take advantage of the resource represented by the brainpower of a few would-be engineers who were serving their mandatory one year in the Army before heading to University. I not only supposedly had the brainpower, I also had the right contacts; in particular, I had friends who were able to loan me an SR-60 desktop calculator that I took with me to the barracks on several occasions. It is for this reason alone that I decided to include an SR-60 in my collection; generally, my interest is confined to portable, battery-operated programmables, and portable the SR-60 most enthusiastically isn't!

This machine is rather huge. (In fact, the reason why it's shown in a relatively low quality photograph here is that even its keyboard is too large for my 8.5" by 13.5" flatbed scanner.) Comparable to similar desktop models from Hewlett-Packard and others, the SR-60 was several years late in coming and looked somewhat outdated even when it was new.

I have recently acquired one of these vintage machines. It was not in good working condition, but I was able to locate the cause: in addition to corroded connectors (several dozen chips in the machine are in sockets) I identified a faulty memory chip. Fortunately, the machine had optional memory modules that I was able to cannibalize to restore its base memory to good working condition.

Without the add-on memory, my SR-60 supports 480 program steps and 40 memory registers. Compared to many pocket calculators, this is a huge amount of storage (although somewhat less than the storage offered by the TI-59). Compared to even the most vintage desktop computers, it is a tiny amount. In the absence of documentation, I have not yet been able to determine how to repartition this machine's memory, even though I distinctly recall that it is possible to do so.

Despite its huge size, the SR-60 is a plain old keystroke programmable scientific calculator. Its programming model is completely unmerged; register operations, for instance, require up to 4 steps of program memory (e.g., RCL 1 0 0.) The good news is that leading zeroes can be omitted from memory indices or program addresses (in fact, when using memory 0, you don't need to type a single zero.) Programming is greatly aided by the calculator's alphanumeric display, that shows keystroke mnemonics instead of numeric keycodes.

I'd like to obtain a few magnetic cards for this machine (boy, are they ever huge!) but even in their absence, I was able to write a few test programs. One of them, of course, is a program that implements the Gamma function:

This Web page copyright ©2005 Viktor T. Toth Page last modified: February 13, 2004

This Web page copyright ©2005 Viktor T. Toth
Page last modified: February 13, 2004