Category Archives: 701

701, Version 1.05

Lots of little bug fixes, and one big one: I had overlooked that the address on STOP is that of the next instruction to be executed if START is hit, and had been using various numbers to distinguish one stop from another. I’ve revised the examples, so you should get new copies of them all. And, if you’ve written any of your own programs, make sure you change the STOP statement if you’ve done what I did.

You’re now allowed to code an + or – offset with an asterisk address (*+1, *-3, etc.), so if you just want to stop and pick up with the next instruction, you can code:

STOP *+1

I’ve added a bunch of new material to Programming the IBM 701, including, finally, information about the assembler.

701, Version 1.04

Assembler now loads only as many cards as needed, instead of enough (86) to hold all of memory. Important now that the card reader operates at close to 711 speeds. A few other tweaks, too, and more examples. (Choose Copy Examples on the File menu to get to the examples.) Examples are written in assembly language, which I’ll explain in Programming the IBM 701¬†soon.

701 Emulator, Version 1.03

A bunch of tweaks, and one larger change: Timing is now much more realistic, reduced to 701 speeds. I/O timing is an approximation, using a simpler model than the 701 itself. For example, the line printer prints at close to 150 lines-per-minute, as it should. The previous version printed much too fast. Also, there are some examples that you can copy with a command on the File menu.

“Programming the IBM 701” has some content

I’ve started to write the document, and there are a few pages that will help get you started, lavishly illustrated. I’ll try to upload the emulator itself tomorrow. Also, IBM has informed me that the essential manual,¬†Principles of Operation Type 701 and Associated Equipment, is in the public domain, so there’s a link to it, too.