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  • AK6DN's Avatar
    Today, 01:04 PM
    AK6DN replied to a thread PDP11/84 Front Panel Pinout in DEC
    That is correct, 11/73/83/93 are QBUS (odd numbers), 11/84/94 are UNIBUS (even numbers). UNIBUS has INIT_L, ACLO_L, DCLO_L signals; QBUS has...
    3 replies | 50 view(s)
  • AK6DN's Avatar
    Today, 09:02 AM
    AK6DN replied to a thread PDP11/84 Front Panel Pinout in DEC
    In this document: EK-1184A-TM-PR2 Preliminary PDP-1184 System Installation And Technical Reference Manual.pdf available on bitsavers as: ...
    3 replies | 50 view(s)
  • AK6DN's Avatar
    May 19th, 2018, 09:39 AM
    Hmmm when I tried to go there I got this:Infected webpage detected now Feature: Web Protection This webpage...
    8 replies | 376 view(s)
  • AK6DN's Avatar
    May 17th, 2018, 07:51 PM
    AK6DN started a thread PDP-8/s on Ebay in DEC
    https://www.ebay.com/itm/PDP-8-S-Serial-Number-0/323259488407?hash=item4b43c45897:g:J6kAAOSw1fJa~I5s for those with an incredible amount of money...
    6 replies | 345 view(s)
  • AK6DN's Avatar
    May 16th, 2018, 03:22 PM
    Yes. The skip only influences whether there is an extra PC+1 applied if the skip condition is met. All other microcoded operations (CLA, HLT, OSR)...
    6 replies | 189 view(s)
  • AK6DN's Avatar
    May 16th, 2018, 12:38 PM
    Correct. Per the little snippet I posted: If bit=0, then bits SMA(AC=1) SZA(AC=0) SNL(L=1) are logically OR'ed to skip If bit=1, then bits...
    6 replies | 189 view(s)
  • AK6DN's Avatar
    May 16th, 2018, 10:38 AM
    From the PDP-8 small computer manual: so when you code SPA SNA both must be true to skip, so it will skip only on AC>0 (ie, AC>=0 && AC!=0)
    6 replies | 189 view(s)
  • AK6DN's Avatar
    April 30th, 2018, 01:15 PM
    Yes, but best be careful here. The ABT series typical delay for a bus driver (eg ABT240) is on the order of 1 to 5ns. This implies a very fast slew...
    15 replies | 836 view(s)
  • AK6DN's Avatar
    April 27th, 2018, 05:07 PM
    AK6DN replied to a thread Yet another TU-58 emulator in DEC
    For doing binary image copies to removable media (SDcard, CFcard, SCSI disk on a pc with PCI scsi adapter) I've used 'dd' from within the CYGWIN...
    14 replies | 846 view(s)
  • AK6DN's Avatar
    April 27th, 2018, 12:44 PM
    AK6DN replied to a thread Yet another TU-58 emulator in DEC
    Got it. I've never tried more than 4 units on XXDP (or RT11), so I can't say if DD255: (or DD377: octal?) (or DD8: or above) would even be legal,...
    14 replies | 846 view(s)
  • AK6DN's Avatar
    April 27th, 2018, 11:33 AM
    AK6DN replied to a thread Yet another TU-58 emulator in DEC
    I just have a few questions: 1) Why not use a 74HCT299 or 74HCT595 part in place of the GAL16V8? The GAL is really not buying you much if at all...
    14 replies | 846 view(s)
  • AK6DN's Avatar
    April 26th, 2018, 05:57 PM
    Certainly not impossible, depends how much work you are willing to put in acquiring and configuring and testing various boards & peripherals. Or...
    7 replies | 575 view(s)
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Recent Entries

RX01/RX02 Drive Emulator using Arduino and a custom shield

by AK6DN on February 4th, 2017 at 09:00 PM
Late in 2015, after retiring from full time work, I dug out my half-finished-never-quite-got-to-work PIC18F4550-based RX02 emulator project from about 10 years ago. It was based on the Dickman RXM code base ported to a USB capable PIC18 device. The intent was to emulate the RX02 device interface with a USB serial backend to a PC running my TU58EM code, kind of like a version of serial disk for the RX interface, with TU58EM as the server. For various reasons I was never able to get a stable USB comm

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Updated February 5th, 2017 at 08:49 PM by AK6DN

Categories
DEC

RX01/RX02 Emulator Passes PDP-11 Diagnostics!

by AK6DN on February 3rd, 2017 at 02:54 PM
So, mega success. I was finally able to get my RX02 emulator passing all three DEC RX02/RX211 diagnostics:

(1) ZXRDC0 : RX02 SS PERF EXER (it has been doing this for a while)
(2) ZRXEA0 : RX02 FMTR PROG (just tonight!)
(3) ZRXFB0 : RX02 FUNCTION-LOGIC TEST (just tonight!)

ZXRF the RX02/RX211 hardware function/logic diagnostic is the big one. Fooling the DEC diagnostic with the RX02 emulator so that this test passes 100% turned out to be a non-trival debugging

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Updated February 4th, 2017 at 09:21 PM by AK6DN

Categories
DEC

DEC XXDP Image Manipulation - xxdpdir

by AK6DN on February 3rd, 2017 at 02:47 PM
So ... over the past month I was able (finally) to finish and test my version of XXDPDIR (actually xxdpdir.pl plus an XXDP.pm Perl module) that supports access to RX01 and RX02 media images (as well as simple linear block drives like TU58, MSCP, RL02, etc) so I could now build RX01 and RX02 bootable XXDP file systems just like I did for TU58 bootable XXDP filesystems. It is written in plain jane Perl, so I run it under CYGWIN 32b on Win7 64b, but it will run on just about any OS that supports Perl,

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Updated February 4th, 2017 at 07:02 PM by AK6DN

Categories
DEC

PDP-11 (or 8) worthwhile without disk drives?

by AK6DN on February 3rd, 2017 at 02:43 PM
There are several options for both PDP-11 and PDP-8 that don't use legacy spinning magnetic media.

PDP-11 TU58EM TU-58 emulator. Requires a Windows/Linux PC or equivalent to run the emulator server code (see https://github.com/AK6DN/tu58em) and an extra serial port on the PDP-11 as the hardware interface. Capable of running XXDP diagnostic images (useful for debug, not much else) but also large enough for a minimal RT-11 system. Search this forum for TU58EM, should find lots of activity.

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Updated February 4th, 2017 at 07:02 PM by AK6DN

Categories
DEC