>< IIRC the Pro 325 uses an F11 as well, although I've not seen one.
>
>The pro325 and 350 are the same machine save for the 325 is floppy only
>and the 350 had floppy and hard disk.
Right...
>< I am not suprised. Although there's a PDP11 CPU in there, the I/O
><system and interrupt structure is nothing like any other PDP11...
>
>the primary thing was the memory mapped video. the PDT-11 also had
>strange IO.
The PDT-130 and -150 both used the same device driver (PD), though
they would display as different device codes, if I remember. The
interesting thing about them was the fact that the firmware knew
about RT-11 queue elements, so all the driver had to do was take the
queue element and pass it to the ROM, which handled the IO, returning
if there was an error, or when the request was satisfied. The driver
then returned to the monitor the completed queue element.
The PDTs were also interesting in that they used an 8085 (later an
8085A) to handle the IO page. Word accesses were about 90ms, byte
accesses were about 180ms if I remember correctly, and we had to
avoid any read-modify-write instructions (BIS/BIC) otherwise it would
take twice as long as the 90ms/180ms...
Finally, an interesting point, the PDT-11/110, which had no storage
devices, had code in ROM which understood the same protocol as the
GT40 for downloading code...
Somewhere I have a program I wrote for use at a science fiction
convention (worldcon-1980, in boston) where I used a PDT-11/150
to download a GT40 with various programs like lunar lander or
roses, or bowling, etc... (The favorite, of course, was lunar
lander)
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '_at_' in place of '!' |
| 110 Spitbrook Rd. ZK03-2/T43 | URL:
http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
Received on Fri Oct 02 1998 - 22:00:54 BST