Talk:ITS machine configurations - Revision history

Jnc: /* MC configuration */ ID of the other MC boxes

2025-09-23T00:43:07Z

‎MC configuration: ID of the other MC boxes

Jnc: /* Still to do */ typo

2024-07-26T19:52:31Z

‎Still to do: typo

Jnc: /* Plasma */ I don't recall the NW16 one

2024-02-17T14:47:09Z

‎Plasma: I don't recall the NW16 one

Larsbrinkhoff: Plasma confusion.

2024-02-17T13:33:45Z

Plasma confusion.

Jnc: /* Fabridreck */ Go for it!

2024-02-12T12:18:16Z

‎Fabridreck: Go for it!

Larsbrinkhoff: /* Fabridreck */ New one to me.

2024-02-12T06:56:33Z

‎Fabridreck: New one to me.

Jnc: /* Fabridreck */ new section

2024-02-11T15:39:00Z

‎Fabridreck: new section

Jnc: /* A good source */ new section

2024-02-10T16:43:49Z

‎A good source: new section

Jnc: /* Still to do */ So, it _wasn't_ a TU45; but we now know what it was (a TU77)

2024-02-08T04:05:53Z

‎Still to do: So, it _wasn't_ a TU45; but we now know what it was (a TU77)

Jnc: /* Still to do */ AI-KS almost certainly had a TU45

2024-02-07T16:28:01Z

‎Still to do: AI-KS almost certainly had a TU45

← Older revision		Revision as of 00:43, 23 September 2025
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	Stephen Jones from the LCM called me last night; he's started exploring MC's remains (and the other stuff they got from Peter Löthberg - principally two CADR's), apparently with a view to getting it running, so in the near future we should have a confirmed list of everything on MC. It's still pretty complete, apparently (the CADR's are missing their keyboards). [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 13:24, 26 October 2022 (CEST)		Stephen Jones from the LCM called me last night; he's started exploring MC's remains (and the other stuff they got from Peter Löthberg - principally two CADR's), apparently with a view to getting it running, so in the near future we should have a confirmed list of everything on MC. It's still pretty complete, apparently (the CADR's are missing their keyboards). [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 13:24, 26 October 2022 (CEST)
		+
		+	[[Technology Square]] claims that the order of the boxes in the right hand corner is "from right, the TM10, its DF10, the DL10, the 'I/O-11'". This seems to be correct; the [http://bitsavers.org/pdf/dec/pdp10/periph/A-MN-DF10-C_MAN1_DF10-C_Data_Channel_Maintenance_Manual_Oct74.pdf DF10-C Data Channel Maintenance Manual] shows (pg. 17 of the PDF) the DF10 light panel, which clearly identifies the second box from the right as the DF10. The image in the [http://bitsavers.org/pdf/dec/pdp10/periph/DEC-10-HTMB-D_TM10_Maint_Sep73.pdf TM10 Maintenance Manual] (on pg. 13) does seem to match the other box.
		+
		+	There do not seem to be any images which clearly show the RH10 and DF10 on the left end of the other bank of boxes; if there were, the [https://bitsavers.org/pdf/dec/pdp10/periph/EK-RH10-MM-002_RH10_Massbus_Controller_Maintenance_Manual_Jun75.pdf RH10 Massbus Controller Maintenance Manual] panel (pg. 11), with its 5 rows of lights, would be easy to identify. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 00:42, 23 September 2025 (UTC)

	== DM/ML configuration ==		== DM/ML configuration ==

@@ Line 138: / Line 138: @@
 * Apparently none of the other KS10's had a tape drive, even MC-KS. This is plausible; they could have been backed up over the Chaosnet. It would be good to confirm that, though.
 * Did MD-KS really have an [[RM80 Disk Drive]], and nothing else? The thing is, that's a non-removable-media disk, so . . . how did the bits get into the machine, to start with? I guess it would have been feasible to cable that drive into another machine to load bits onto it, though. (MC-KS and ML-KS both had RP06's, so they could have used packs written on AI-KS.)
-* It would be nice to know what the other moby on DM (not the two MD10's was); I vaguely recollect it being a mashup of early DEC memory boxes (MA10's, MB10's). That will probably be hard to figure out.
+* It would be nice to know what the other moby on DM (not the two MD10's) was; I vaguely recollect it being a mashup of early DEC memory boxes (MA10's, MB10's). That will probably be hard to figure out.
 * Serial line interfaces on all the machines (other than MC).
 * Did the TM10B on DM have its own DF10, or did it share the RP10's?

← Older revision		Revision as of 14:47, 17 February 2024
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	==Plasma==		==Plasma==

−	I find it confusing, but I believe there were two "Plasma" groups/departments, correct? One in Building 38, sometimes referred to as the Plasma Group (and Plasma Physics?). Another in NW16, the Plasma Fusion Center. The one in Building 38 had the Gould printer and a TV system with Grinnell frame buffers; maybe it was called the R11/RTTY11/CHSGTV. The one in NW16 ''also'' had a TV system; maybe KTV.	+	I find it confusing, but I believe there were two "Plasma" groups/departments, correct? One in Building 38, sometimes referred to as the Plasma Group (and Plasma Physics?). Another in NW16, the Plasma Fusion Center. The one in Building 38 had the Gould printer and a TV system with Grinnell frame buffers; maybe it was called the R11/RTTY11/CHSGTV. The one in NW16 ''also'' had a TV system; maybe KTV. [[User:Larsbrinkhoff\|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff\|talk]]) 13:33, 17 February 2024
		+
		+	: I don't recall the NW16 one; all the Tech Sq interaction with the 'Plasma people' that I recall was with the Building 38 people. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 15:47, 17 February 2024 (CET)

← Older revision		Revision as of 13:33, 17 February 2024
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	:: Go for it! [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 13:18, 12 February 2024 (CET)		:: Go for it! [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 13:18, 12 February 2024 (CET)
		+
		+	==Plasma==
		+
		+	I find it confusing, but I believe there were two "Plasma" groups/departments, correct? One in Building 38, sometimes referred to as the Plasma Group (and Plasma Physics?). Another in NW16, the Plasma Fusion Center. The one in Building 38 had the Gould printer and a TV system with Grinnell frame buffers; maybe it was called the R11/RTTY11/CHSGTV. The one in NW16 ''also'' had a TV system; maybe KTV.

@@ Line 161: / Line 161: @@
 I was wondering, when I first saw those speed numbers in the ARH, if, based on the speed difference between it and the Ampex, if the Ampex was assigned to a low absolute address, so the OS was housed in it, leaving the Fabritek to be used entirely for housing user code? 'Obviously', if one has two speeds of memory (and the speed difference was really large, which was why I thought it worth noting), it would ''generally'' (I am guessing) be better to have the OS running out of the faster memory. (On a general-purpose time-sharing system, with lots of simultaneous users; on a system primarily used for big number-crunching applications, not so much.)
-If so (on the location assignment guess), a side-benefit would be that the 'flakier' memory would hold user processes, and the system is more likely to be able to deal with memory errors in user processes than those in the OS. (I don't recall how ITS handled the two cases, but in UNIX it just kills the process if it was user memory that got the error:
+If so (on the location assignment guess), a side-benefit would be that the 'flakier' memory would hold user processes, and the system is more likely to be able to deal with memory errors in user processes than those in the OS. (I don't recall how ITS handled the two cases, but in UNIX if it was user memory that got the error it just kills the process:
                  printf("mem error");
@@ Line 178: / Line 178: @@
 : Huh, I have actually never seen "fabridreck" before.  I understand it took a year or so from delivery for the full 256K to be working (somewhat?) reliably, so it certainly seen to have been flaky from the beginning.  I don't know which memories went where in the address space.
 : I have seen plenty of other nicknames like memowreck, dissapoint, etc.  So I can see it was a tradition.  Maybe these should be collected in a separate article. [[User:Larsbrinkhoff|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff|talk]]) 07:56, 12 February 2024 (CET)

← Older revision		Revision as of 06:56, 12 February 2024
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	I don't know if the Fabritek really ''was'' more temperamental and flaky than the Ampex (i.e. there was ''data'' showing that it was), or if the hackers just ''assumed'' it was. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 16:39, 11 February 2024 (CET)		I don't know if the Fabritek really ''was'' more temperamental and flaky than the Ampex (i.e. there was ''data'' showing that it was), or if the hackers just ''assumed'' it was. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 16:39, 11 February 2024 (CET)
		+
		+	: Huh, I have actually never seen "fabridreck" before. I understand it took a year or so from delivery for the full 256K to be working (somewhat?) reliably, so it certainly seen to have been flaky from the beginning. I don't know which memories went where in the address space.
		+	: I have seen plenty of other nicknames like memowreck, dissapoint, etc. So I can see it was a tradition. Maybe these should be collected in a separate article. [[User:Larsbrinkhoff\|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff\|talk]]) 07:56, 12 February 2024 (CET)

← Older revision		Revision as of 15:39, 11 February 2024
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	Look in the 'Hardware' section. (The other sections are interesting too.) Don't take that all too literally; e.g. the ML entry says it has "6 x RP02" disks, which was never correct while I was there; the [[RP02]] has a vertical front face, and the [[RP03]] a slanted one (see the images I am about to add), and I'm fairly sure ML had RP03's - and only 4 of them. (ISTR that the salvager or something will confirm the sizes, which will confirm.) [https://github.com/PDP-10/its-vault/blob/master/files/_info_/shut.down SHUT DOWN] confirms my memory that AI had 8 [[Calcomp 215]]s (also coming soon), not 6. And DM never had an RK05. I'm not sure about AI having two TU20s; it's possible. But that list is generally correct. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 17:43, 10 February 2024 (CET)		Look in the 'Hardware' section. (The other sections are interesting too.) Don't take that all too literally; e.g. the ML entry says it has "6 x RP02" disks, which was never correct while I was there; the [[RP02]] has a vertical front face, and the [[RP03]] a slanted one (see the images I am about to add), and I'm fairly sure ML had RP03's - and only 4 of them. (ISTR that the salvager or something will confirm the sizes, which will confirm.) [https://github.com/PDP-10/its-vault/blob/master/files/_info_/shut.down SHUT DOWN] confirms my memory that AI had 8 [[Calcomp 215]]s (also coming soon), not 6. And DM never had an RK05. I'm not sure about AI having two TU20s; it's possible. But that list is generally correct. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 17:43, 10 February 2024 (CET)
		+
		+	== Fabridreck ==
		+
		+	Old Tech Sq jargon! (I didn't create it; I just remember it being used.) I assume that was because, compared to later memories (it was ''really'' early, having been attached to the -6), it was temperamental, and more flaky. (Although obviously not so temperamental and flaky that it was unusable in a large time-sharing system.)
		+
		+	I was wondering, when I first saw those speed numbers in the ARH, if, based on the speed difference between it and the Ampex, if the Ampex was assigned to a low absolute address, so the OS was housed in it, leaving the Fabritek to be used entirely for housing user code? 'Obviously', if one has two speeds of memory (and the speed difference was really large, which was why I thought it worth noting), it would ''generally'' (I am guessing) be better to have the OS running out of the faster memory. (On a general-purpose time-sharing system, with lots of simultaneous users; on a system primarily used for big number-crunching applications, not so much.)
		+
		+	If so (on the location assignment guess), a side-benefit would be that the 'flakier' memory would hold user processes, and the system is more likely to be able to deal with memory errors in user processes than those in the OS. (I don't recall how ITS handled the two cases, but in UNIX it just kills the process if it was user memory that got the error:
		+
		+	printf("mem error");
		+	if (cputype == 70)
		+	printf(": %o %o", MEMORY->r[1], MEMORY->r[0]);
		+	if (dev & USER) {
		+	i = SIGBUS;
		+	break;
		+	}
		+	panic("kernel mode mem fault");
		+
		+	and continues on its merry way, while a memory error in the OS kills the system.)
		+
		+	I don't know if the Fabritek really ''was'' more temperamental and flaky than the Ampex (i.e. there was ''data'' showing that it was), or if the hackers just ''assumed'' it was. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 16:39, 11 February 2024 (CET)

← Older revision		Revision as of 16:43, 10 February 2024
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	I guess that's all I have for the moment. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 03:31, 7 February 2024 (CET)		I guess that's all I have for the moment. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 03:31, 7 February 2024 (CET)
		+
		+	== A good source ==
		+
		+	See the [https://books.google.com/books?id=XxveYHLCcKoC&pg=PA355&lpg=PA355&source=bl&ots=IFJA_P9-8E&sig=ACfU3U2Rl7wZaBjAtPnYoHWgTXMSbySsfw&hl=en&sa=X&ved=2ahUKEwitxZ6J-6CEAxU-EVkFHWAxAHcQ6AF6BAgcEAM#v=onepage&f=false Arpanet Resources Handbook]:
		+
		+	* AI: pg. 355-370
		+	* DM: pg. 373-389
		+	* MC: pg. 391-398
		+	* ML: pg. 399-404
		+
		+	Look in the 'Hardware' section. (The other sections are interesting too.) Don't take that all too literally; e.g. the ML entry says it has "6 x RP02" disks, which was never correct while I was there; the [[RP02]] has a vertical front face, and the [[RP03]] a slanted one (see the images I am about to add), and I'm fairly sure ML had RP03's - and only 4 of them. (ISTR that the salvager or something will confirm the sizes, which will confirm.) [https://github.com/PDP-10/its-vault/blob/master/files/_info_/shut.down SHUT DOWN] confirms my memory that AI had 8 [[Calcomp 215]]s (also coming soon), not 6. And DM never had an RK05. I'm not sure about AI having two TU20s; it's possible. But that list is generally correct. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 17:43, 10 February 2024 (CET)

@@ Line 135: / Line 135: @@
 * Confirm whether AI-KS had a [[TU45]] or [[TU78]]. [http://www.bitsavers.org/pdf/dec/pdp10/KS10/EK-KS10-TM-PRE_tech_Feb78.pdf EK-KS10-TM-PRE] (and probably other places) say that 'DEC FS will not maintain systems that do not have a TU45', but . . . [https://github.com/PDP-10/its/blob/master/src/system/tm78s.defs2 SYSTEM;TM78S DEFS2] exists. So maybe it had a TU78? On the gripping hand, [https://github.com/PDP-10/its/blob/master/src/system/nmtape.30 NMTAPE 30] doesn't seem to use any symbols from there, it seems to only use things from [https://github.com/PDP-10/its/blob/master/src/system/tm03s.defs5 TM03S DEFS5] (which doesn't seem to have anything drive-specific in it), so maybe it was a TU45 after all? Did the [[TM03]] even support a TU78?
 ** Now that I think about it, it was almost certainly a TU45. The TU78 uses a [[TM78 Magnetic Tape Formatter|TM78]] formatter, which plugs into the MASSBUS. But [https://github.com/PDP-10/its-vault/blob/master/files/system/config.186 CONFIG 186] says that AI-KS had a TM03 ("DEFOPT TM03S==1"); and the TM03 ''also'' connects to the MASSBUS - i.e. one wouldn't have both. So if it didn't have a TM78 it could't have had a TU78. Q.E.D. (Although I suppose it could have had a [[TU77]].) [[User:Jnc|Jnc]] ([[User talk:Jnc|talk]]) 17:25, 7 February 2024 (CET)
 * Apparently none of the other KS10's had a tape drive, even MC-KS. This is plausible; they could have been backed up over the Chaosnet. It would be good to confirm that, though.
 * Did MD-KS really have an [[RM80 Disk Drive]], and nothing else? The thing is, that's a non-removable-media disk, so . . . how did the bits get into the machine, to start with? I guess it would have been feasible to cable that drive into another machine to load bits onto it, though. (MC-KS and ML-KS both had RP06's, so they could have used packs written on AI-KS.)