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Questions tagged [dec]

For questions regarding the hardware, software and peripheral products of DEC - The Digital Equipment Corporation.

6
votes
1answer
158 views

Origin of the NZVC condition codes scheme?

The NZVC condition codes scheme, and corresponding set of 14 conditions for branches, is the nearly only in current ISAs that utilizes condition codes at all. The first computer I know that used it is ...
5
votes
0answers
113 views

Do you have a non-paging ITS for PDP-6 or PDP-10?

In the early days (late 60s), the Incompatible Timesharing System ran on a PDP-6 without any paging hardware (i.e. an MMU in modern terminology). (See "The Big BLT".) It was later moved onto a PDP-...
16
votes
2answers
871 views

How widely used was 0xDEADBEEF?

Inspired by some comments on the question "The history of the NULL pointer":- There was a practice in the '70s to use the hexadecimal code 0xDEADBEEF to indicate an invalid value. This could be to ...
19
votes
5answers
2k views

Were there any LSI-11 like home computers outside of Russia?

In my childhood I had one of these: https://en.wikipedia.org/wiki/Electronika_BK Note, that the CPU of this is based on LSI-11. This is rather surprising because PDP-11 took a room (I was lucky ...
7
votes
1answer
209 views

Was there an interactive macro/scripting language named PAGEN?

In a BESM-6 disk image I can see bits and pieces of something that looks like a strange interactive scripting language: [start of disk block] <LET=P11=%X01 <IEQ=P11=%377 <LET=P11=1 <END &...
9
votes
1answer
330 views

What does bold reverse video look like on a VT100/VT102?

My understanding is that bold text on a VT100/VT102 is more intense than ordinary text; I might say that normal text is 80% grey and bold text is 100% grey=pure white, for the sake of illustration. ...
9
votes
1answer
341 views

Typical mid-scale business computer system of the late 70s

What was the most common business computer system of the late 70s, just before the Apple II and CP/M really started proliferating? For concreteness, let's say we are talking about a U.S. company on ...
6
votes
2answers
148 views

DECNet physical connector

DECNet was a network system for DEC computers, introduced in the mid to late seventies. What physical connector did it use? Was it possible to connect to such a network using just an RS-232 serial ...
10
votes
1answer
280 views

On-disk structures for Files-11 format (RSX11)

I'm looking for an explanation, or a link to documentation of the on-disk structures of the Files-11 format, that is, the format of disks used by RSX-11 on the PDP-11. Also known as ODS-1, the ...
15
votes
3answers
568 views

Conditional skip instructions of the PDP-8

I am interested in the SKIP instructions on the PDP-8. These test the accumulator and Link bit, and they skip the next instruction if the condition holds. The instructions are: OR GROUP SMA - Skip ...
13
votes
1answer
183 views

What happens on a VT102 when you use delete character on a reverse video line?

On a DEC VT102, suppose you have a line where all 80 characters (in particular, the rightmost character) are in reverse video. You then move the cursor to the start of that line and use DCH (ESC [ P) ...
18
votes
3answers
419 views

Where can I find software for the PDP-6?

We are planning to build a reconstruction of the PDP-6. The project is making a lot of progress, but currently we have a critical lack of software. Does anybody know where we can find software to run ...