Re: Scan of Micro Peripherals Inc MPI 91/92 Product Manual Avail?
On 10/4/2018 8:34 PM, Bill Degnan via cctalk wrote: I got a request for a scan of the Micro Peripherals Inc MPI 91/92 Product Manual. I have the manual, I will scan it and post if no one has a copy. But I don't want to go through the effort if it exists somewhere already. I noticed on bitsavers there was no MPI nor Micro Peripherals Inc section so it very well may be that there is no copy of this manual out there.. Thanks in advance. Bill Is this the floppy drive outfit in Chatsworth or there bouts? I serviced their inhouse Microdata Reality system, and later converted them to a Compaq 386 running Pick for the AT. "Would work for floppy drives" was on my sign I used for begging. It came in handy before we replaced the Reality system as drives were expensive and on allocation a lot, and we obviously had no problem with that. I'd love to have the manual, as I think I've got some of the drives it that is what these are. I initially confused the MPI with the CDC tape division, but then realized you likely meant the floppy folks, at any case, not the CDC division. thanks Jim
Scan of Micro Peripherals Inc MPI 91/92 Product Manual Avail?
I got a request for a scan of the Micro Peripherals Inc MPI 91/92 Product Manual. I have the manual, I will scan it and post if no one has a copy. But I don't want to go through the effort if it exists somewhere already. I noticed on bitsavers there was no MPI nor Micro Peripherals Inc section so it very well may be that there is no copy of this manual out there.. Thanks in advance. Bill
Re: Ethernet names...
On Thu, Oct 4, 2018, 14:19 Eric Smith wrote: > except that in the Pelkey account the Alto network wasn't designed and > built until June, _after_ the name change. > I should have written that it the design and construction _started_ in June. The initial Ethernet wasn't completed until late 1974.
Ethernet names...
> From: Eric Smith > I think the account given in the book may be a bit confused on this > point. ... That sequence of events is contradicted by Pelkey ... > describes the name change from Alto Aloha to Ether as happening in May > 1973 in agreement with WWSUL, except that in the Pelkey account the > Alto network wasn't designed and built until June, _after_ the name > change. It's quite possible that in Metcalfe's interview (which is what the WWSUL account seems to be pretty much wholly based on), N years after it all happened, his memory flaked and he got the sequence wrong. I've had the same thing happen to me, trying to recall the sequence/timing of early IP work at MIT. I was sure X happened before Y, and then Jerry Saltzer dug up an old progress report... There's a reason that the gold standard for historians is contemporary documentation. Along those lines, here: http://www.chiappa.net/~jnc/nontech/tmlotus.html is an amusing story of my encounters with this effect on some Lotus Indycar research I did. Noel
Re: Ethernet names...
On 10/02/2018 09:20 PM, Bill Degnan via cctalk wrote: I think Metcalfe was just giving credit for where he got the idea of letting packets collide like alohanet was doing. He took their idea and improved with collision detection and borrowed the name of his improvements and subsequent network "The Alto Aloha Network" i.e. it was his improved "alto" version of the concept inspired by alohanet. In May 1973 (I later found) he renamed his network system "Ethernet". There were a number of other more established networks out there at the time, this was just the start. I think this whole area of research is very interesting. According to the following link (which is purportedly an excerpt from page 5 of "Ethernet: The Definitive Guide"), the 3 Mbps Experimental Ethernet was indeed originally called Ethernet. Link - Why is it called Ethernet? - http://www.ethermanage.com/why-is-it-called-ethernet/ """ In late 1972, Metcalfe and his Xerox PARC colleagues developed the first experimental “Ethernet” network system to interconnect Xerox Altos to one another, and to servers and laser printers. The signal clock for the experimental interface was derived from the Alto’s system clock, resulting in a data transmission rate on the experimental Ethernet of 2.94 Mb/s. Metcalfe’s first experimental network was called the Alto Aloha Network. In 1973, Metcalfe changed the name to “Ethernet,” to make it clear that the system could support any computer‚ not just Altos‚ and to point out that his new network mechanisms had evolved well beyond the Aloha system. He chose to base the name on the word “ether” as a way of describing an essential feature of the system: the physical medium (i.e., a cable) carries bits to all stations, much the same way that the old “luminiferous ether” was once thought to propagate electromagnetic waves through space. Thus, Ethernet was born. """ I apparently need to pick up a copy of Ethernet: The Definitive Guide and do some reading. -- Grant. . . . unix || die
Re: PDP-15 documentation
On Thu, Oct 4, 2018 at 5:18 PM Mattis Lind via cctalk wrote: > > I have now finally concluded the PDP-15 documentation scanning project. > Thanks for doing this! -- Regards, Torfinn Ingolfsen
Re: Ethernet names...
On 10/04/2018 12:16 PM, Paul Koning via cctalk wrote: I had to look up SQE. http://www.ethermanage.com/ethernet/sqe/sqe.html It's 802-speak for the same signal. I agree that it's the same concept and function. Though the link you shared states that there is some timing difference between D.I.X.'s "Collision Presence Test" (CPT) and IEEE's 802.3 "Signal Quality Error" (SQE). That page says you have to turn it off for the transceiver connected to an 802.3 repeater, but it should be on in all other cases. Sounds like the 802.3 people got the transceiver design wrong and that rule is a workaround. There certainly is no similar rule in the Ethernet spec, and repeaters are definitely part of that spec. Given that CPT / SQE / HB are between the transceiver and the host NIC, and NOT between the transceiver and the Ethernet, IMHO it makes sense that CPT / SQE / HB should not be used with a repeater. After all, a repeater is going between two (or more?) Ethernet segments. As such, I don't think it's a problem with the specification or design of transceivers. I think the CPT / SQE / HB are in some ways a feedback loop between the transceiver and the NIC to test the collision detection circuitry in the NIC. -- Grant. . . . unix || die
Re: Ethernet names...
The typo(s) in the quote are mine, not the book's.
Re: DG microNOVA in Cleveland on CL
On Thu, Oct 04, 2018 at 03:37:59PM -0400, Bill Degnan via cctalk wrote: > oops sorry I mean I did not get it. dang, and I already had my samurai sword nearly sharpened. mcl
Re: Ethernet names...
On Thu, Oct 4, 2018 at 1:55 PM Bill Degnan wrote: > I must have misrepresented this then, the book does claim Aloha Net to be > just a working name in the very beginning. When it got to the beta testing > phase it was already called Ethernet > After you referenced _Where Wizards Stay Up Late_, I reread the relevant portions, and I don't think you misrepresented what the book said. I think the account given in the book may be a bit confused on this point. For example, on page 239: Metcalfe and Lampson, along with Xerox researchers David Boogs and Chuck Thacker, built their first Alto Aloha system in Bob Taylor's lab at Xerox PARC. To their great delight, it worked. In May 1973 Metcalfe suggested a name, [...] My interpretation of that would be that they built it, had something basically working, were calling it Alto Aloha, and then later Metcalfe named in Ethernet. That sequence of events is contradicted by Pelkey, and my guess is that Pelkey is more authoritative on this point. Pelkey describes the name change from Alto Aloha to Ether as happening in May 1973 in agreement with WWSUL, except that in the Pelkey account the Alto network wasn't designed and built until June, _after_ the name change. However, I still think that WWSUL is an excellent book, well worth reading. Eric
Re: Ethernet names...
> > > Thanks! From that, it sounds like the name "Alto Aloha" was only used > during early planning, before CSMA/CD was invented, and that nothing that > was actually built ever used that name, contrary to the account in _Where > Wizards Stay Up Late_. > I must have misrepresented this then, the book does claim Aloha Net to be just a working name in the very beginning. When it got to the beta testing phase it was already called Ethernet b
Re: DG microNOVA in Cleveland on CL
I got it, awesome, tons of gold to scrap. I then sold the keyboard and threw the terminal over the bridge. I just had to tell the guy I was from the museum of computers in Cleveland. oops sorry I mean I did not get it. ha ha On Thu, Oct 4, 2018 at 2:51 PM Ian Primus via cctalk wrote: > Someone linked this to me on IRC. I called, but it was already > claimed. Just hope it gets to a good home. > > -Ian > On Thu, Oct 4, 2018 at 2:32 PM jos via cctalk > wrote: > > > > On 04.10.2018 20:03, John Foust via cctalk wrote: > > > > > > > https://cleveland.craigslist.org/sys/d/data-general-free-for-good/6714121268.html > > > > > > > > > > A MP/200. 16 bit CPU built with AMD2901. > > Rare beast, alas mine doesn't post. Powersupply is OK. > > Lack of schematics / detailed documentations hampers progess > > > > Jos >
Re: DG microNOVA in Cleveland on CL
Someone linked this to me on IRC. I called, but it was already claimed. Just hope it gets to a good home. -Ian On Thu, Oct 4, 2018 at 2:32 PM jos via cctalk wrote: > > On 04.10.2018 20:03, John Foust via cctalk wrote: > > > > https://cleveland.craigslist.org/sys/d/data-general-free-for-good/6714121268.html > > > > > > A MP/200. 16 bit CPU built with AMD2901. > Rare beast, alas mine doesn't post. Powersupply is OK. > Lack of schematics / detailed documentations hampers progess > > Jos
Re: DG microNOVA in Cleveland on CL
On 04.10.2018 20:03, John Foust via cctalk wrote: https://cleveland.craigslist.org/sys/d/data-general-free-for-good/6714121268.html A MP/200. 16 bit CPU built with AMD2901. Rare beast, alas mine doesn't post. Powersupply is OK. Lack of schematics / detailed documentations hampers progess Jos
Re: Ethernet names...
> On Oct 4, 2018, at 1:43 PM, Warner Losh wrote: > > > > On Thu, Oct 4, 2018 at 11:39 AM Paul Koning via cctalk > wrote: > > > > On Oct 4, 2018, at 1:30 PM, Grant Taylor via cctalk > > wrote: > > ... > > That makes me wonder about the "heartbeat" switch that I see on older AUI > > transceivers. > > Yes, I think that's the collision test. So in the OFF position you have a V1 > compatible transceiver, ON is needed for V2. > > Is that the same as SQE? I always had to turn that bad-boy off or risk > collision storms :( > > Warenr I had to look up SQE. http://www.ethermanage.com/ethernet/sqe/sqe.html It's 802-speak for the same signal. That page says you have to turn it off for the transceiver connected to an 802.3 repeater, but it should be on in all other cases. Sounds like the 802.3 people got the transceiver design wrong and that rule is a workaround. There certainly is no similar rule in the Ethernet spec, and repeaters are definitely part of that spec. paul
DG microNOVA in Cleveland on CL
https://cleveland.craigslist.org/sys/d/data-general-free-for-good/6714121268.html
Re: Ethernet names...
On Thu, Oct 4, 2018 at 11:39 AM Paul Koning via cctalk < cctalk@classiccmp.org> wrote: > > > > On Oct 4, 2018, at 1:30 PM, Grant Taylor via cctalk < > cctalk@classiccmp.org> wrote: > > > > On 10/04/2018 11:26 AM, Paul Koning via cctalk wrote: > >> That's sort of accurate. A quick look shows some key differences: V2 > adds the "collision presence test" -- verifying the collision detect signal > is working. There is also the "jabber timer" -- a watchdog timeout that > stops excessively long frames. And V2 introduces the loopback protocol > (protocol type 90-00). > > > > That mostly sounds like the frame formats are the same on the wire and > that the differences are in the protocols that use said frame. > > > >> The collision presence test is somewhat of an interoperability issue: > if you attach a V1 transceiver to a V2 NIC, the NIC would complain on every > transmit that it didn't get the collision test signal. > > > > That makes me wonder about the "heartbeat" switch that I see on older > AUI transceivers. > > Yes, I think that's the collision test. So in the OFF position you have a > V1 compatible transceiver, ON is needed for V2. > Is that the same as SQE? I always had to turn that bad-boy off or risk collision storms :( Warenr
Re: Ethernet names...
> On Oct 4, 2018, at 1:30 PM, Grant Taylor via cctalk > wrote: > > On 10/04/2018 11:26 AM, Paul Koning via cctalk wrote: >> That's sort of accurate. A quick look shows some key differences: V2 adds >> the "collision presence test" -- verifying the collision detect signal is >> working. There is also the "jabber timer" -- a watchdog timeout that stops >> excessively long frames. And V2 introduces the loopback protocol (protocol >> type 90-00). > > That mostly sounds like the frame formats are the same on the wire and that > the differences are in the protocols that use said frame. > >> The collision presence test is somewhat of an interoperability issue: if you >> attach a V1 transceiver to a V2 NIC, the NIC would complain on every >> transmit that it didn't get the collision test signal. > > That makes me wonder about the "heartbeat" switch that I see on older AUI > transceivers. Yes, I think that's the collision test. So in the OFF position you have a V1 compatible transceiver, ON is needed for V2. paul
Re: Ethernet names...
On 10/04/2018 11:26 AM, Paul Koning via cctalk wrote: That's sort of accurate. A quick look shows some key differences: V2 adds the "collision presence test" -- verifying the collision detect signal is working. There is also the "jabber timer" -- a watchdog timeout that stops excessively long frames. And V2 introduces the loopback protocol (protocol type 90-00). That mostly sounds like the frame formats are the same on the wire and that the differences are in the protocols that use said frame. The collision presence test is somewhat of an interoperability issue: if you attach a V1 transceiver to a V2 NIC, the NIC would complain on every transmit that it didn't get the collision test signal. That makes me wonder about the "heartbeat" switch that I see on older AUI transceivers. -- Grant. . . . unix || die
Re: Ethernet names...
> On Oct 4, 2018, at 1:07 PM, Eric Smith via cctalk > wrote: > > On Tue, Oct 2, 2018 at 10:55 PM Grant Taylor via cctalk < > cctalk@classiccmp.org> wrote: > >> On 10/02/2018 05:27 PM, Eric Smith via cctalk wrote: >>> 3 Mbps Ethernet is _NOT_ Ethernet I. Both Ethernet I and II were 10 Mbps >>> DIX standards, with II having only minor differences from I. >> >> Okay. Thank you for the correction ~> clarification. >> >> Now I'll keep an eye out (but not quite search for) the differences >> between Ethernet (I) and Ethernet II > > > The Ethernet I and II standards are available from Bitsavers: >http://bitsavers.trailing-edge.com/pdf/xerox/ethernet/ > > From the preface of _The Ethernet_ Version 2.0: > Version 2.0 of the Ethernet specification reflects the experience of the > three corporations in designing equipment to the Version 1.0 specification. > Version 2.0 includes network management functions and better defines the > details of the physical channel signalling. Version 2.0 is upward > compatible with Version 1.0. Equipment designed to the two specifications > is interoperable. That's sort of accurate. A quick look shows some key differences: V2 adds the "collision presence test" -- verifying the collision detect signal is working. There is also the "jabber timer" -- a watchdog timeout that stops excessively long frames. And V2 introduces the loopback protocol (protocol type 90-00). The collision presence test is somewhat of an interoperability issue: if you attach a V1 transceiver to a V2 NIC, the NIC would complain on every transmit that it didn't get the collision test signal. paul
Re: Ethernet names...
On 10/04/2018 11:07 AM, Eric Smith via cctalk wrote: The Ethernet I and II standards are available from Bitsavers: http://bitsavers.trailing-edge.com/pdf/xerox/ethernet/ Cool. From the preface of _The Ethernet_ Version 2.0: Version 2.0 of the Ethernet specification reflects the experience of the three corporations in designing equipment to the Version 1.0 specification. Version 2.0 includes network management functions and better defines the details of the physical channel signalling. Okay. Intriguing. Version 2.0 is upward compatible with Version 1.0. Equipment designed to the two specifications is interoperable. My brain is having some trouble unpacking and understanding "upward compatible". - I always think that it should be "new version is /downward/ compatible with the old version" or "the old version is /upward/ compatible with the new version". It's also stumbling on "the two specifications is interoperable". Is that "the (version) two specification is interoperable (with the version one specification)" or "the two specification(s) /are/ interoperable"? This might not make much difference. But my brain trips on are they truly 100% interoperable (as in extra fields in version 2 that version 1 ignores) or is it a case of version 1 only understand version 1 and version 2 is able to pretend to be version 1 when talking to version 1? Sort of like a crude diagram: v1 <--->| v2 v1 |<--->| v2 v1 |<---> v2 Which of the three is it? I'll have to check out the documentation on Bitsavers. Thank you for the link. -- Grant. . . . unix || die
Re: Ethernet names...
On Wed, Oct 3, 2018 at 11:21 PM Mark Kahrs via cctalk wrote: > I was there and it was always called "The Ethernet". When the 10 Mb > standard came into being, it was then referred to as "The Experimental > Ethernet". If you want to be *really* pedantic, you could refer to it as > the "2.94 MHz Ethernet" --- but that would be silly. > > If you'd like to see how Aloha inspired Metcalfe, read this: > > > http://www.historyofcomputercommunications.info/Book/6/6.7-EthernetRobertMetcalfeXeroxPARC71-75.html > Thanks! From that, it sounds like the name "Alto Aloha" was only used during early planning, before CSMA/CD was invented, and that nothing that was actually built ever used that name, contrary to the account in _Where Wizards Stay Up Late_.
Re: Ethernet names...
On Tue, Oct 2, 2018 at 10:55 PM Grant Taylor via cctalk < cctalk@classiccmp.org> wrote: > On 10/02/2018 05:27 PM, Eric Smith via cctalk wrote: > > 3 Mbps Ethernet is _NOT_ Ethernet I. Both Ethernet I and II were 10 Mbps > > DIX standards, with II having only minor differences from I. > > Okay. Thank you for the correction ~> clarification. > > Now I'll keep an eye out (but not quite search for) the differences > between Ethernet (I) and Ethernet II The Ethernet I and II standards are available from Bitsavers: http://bitsavers.trailing-edge.com/pdf/xerox/ethernet/ >From the preface of _The Ethernet_ Version 2.0: Version 2.0 of the Ethernet specification reflects the experience of the three corporations in designing equipment to the Version 1.0 specification. Version 2.0 includes network management functions and better defines the details of the physical channel signalling. Version 2.0 is upward compatible with Version 1.0. Equipment designed to the two specifications is interoperable.
Re: Ethernet names...
On 10/04/2018 02:31 AM, Peter Corlett via cctalk wrote: It was probably just known as "Ethernet". If there's only one kind, why give it a longer name to distinguish it from future variants that may never come to be? My bumph tells me it was called "Experimental Ethernet", but I suspect that's a name given to it in retrospect. I agree that the "Experimental" in "Experimental Ethernet" is in fact probably retroactive. "Ethernet I" and "Ethernet II" were 10Mb/s thicknet variants which evolved into the 802.3/10Base5 standards. The exact details of the differences are probably lost in time. The contributions to this thread have satisfied my curiosity / question that "Ethernet (I)" was not the 3 Mbps Experimental Ethernet. Although thicknet is finally dead -- we had to hammer many stakes into the cable to make sure, but managed it in the end -- Um … I'm somewhat reluctant to tell you that there's a Thicknet segment in my basement with transceivers attacked. I've not sent traffic across it /yet/. But I will. ;-) Admittedly, it is purely for edutainment and hobbyist retro-computing / retro-networking reasons. Ethernet II's layer 2 protocol remains in use in modern IP networks, and contemporary usage of "Ethernet II" refers to just that rather than the older standard. Yep. I need to re-read something to see if (a variant of) Ethernet II frames are used for IP on WiFi or if they are closer to 802.2 LLC + SNAP similar to what is used on other, non-Ethernet, 802 networks. -- Grant. . . . unix || die
Re: Source code listings from REDAC PDP-based PCB layout system.
Den tis 2 okt. 2018 kl 00:27 skrev Al Kossow via cctalk < cctalk@classiccmp.org>: > I'm interested. > PDP-15 software in any form is pretty rare > > > Good that we have a taker. I have no such scanner available that could possible scan these in a good way. I will retrieve them and pack them and get back when we get close to shipping. /Mattis
PDP-15 documentation
I have now finally concluded the PDP-15 documentation scanning project. Many year ago my father saved a big lot of PDP-15 documentation that was thrown out from Philips in Stockholm. I have over the years scanned documents on request which has ended up at bitsavers. Some docuements were already present on bitsavers. Now I took a stab and finalised this project. All the remaining PDP-15 has now been scanned and I put them here: http://www.datormuseum.se/documentation-software/pdp-15-documentation Many documents already has made its way to bitsavers but many remains. There are DOS-15, XVM/DOS and various general documents such as operators guide, course handouts etc. The only remaining document to scan is the RSX PLUS III reference manual which will be tricky to scan without damage it. Happy reading!
Re: Ethernet names...
On Tue, Oct 02, 2018 at 11:34:54AM -0600, Grant Taylor via cctalk wrote: > Does anybody know names / terms that correspond to the original 3 Mbps > Ethernet? > I.e. 10 Mbps Ethernet is also knows as Ethernet II (2) and D.I.X. (for > Digital, Intel, and Xerox). > Was the first 3 Mbps Ethernet simply called "Ethernet" with an implicit "I" > (1)? Was there a name to differentiate it from D.I.X.? It was probably just known as "Ethernet". If there's only one kind, why give it a longer name to distinguish it from future variants that may never come to be? My bumph tells me it was called "Experimental Ethernet", but I suspect that's a name given to it in retrospect. "Ethernet I" and "Ethernet II" were 10Mb/s thicknet variants which evolved into the 802.3/10Base5 standards. The exact details of the differences are probably lost in time. Although thicknet is finally dead -- we had to hammer many stakes into the cable to make sure, but managed it in the end -- Ethernet II's layer 2 protocol remains in use in modern IP networks, and contemporary usage of "Ethernet II" refers to just that rather than the older standard.
TK50Z (was: Rack-mount or tabletop version of DEC RX50 floppy drive?)
On Wed, 3 Oct 2018, Adrian Graham wrote: Here?s a pic of my RX50 and TK50. I?ve not tried to power them up for years. Speaking of TK50 and since I'm playing with them at the moment, is there any information on the SCSI command set for the TK50Z? My goal is to talk to one on a Linux system, but the TK50Z is special enough that it won't work as a generic SCSI tape drive, at least by default as it seems. Christian
HP1000 A600 Boards available
Hi, two weeks before I was asked from a friend if it's worth to rescue an HP1000 A600 computer from the stuff available at a local scrapp seller in Erfurt. Of course I've answered yes! Unfortunately someone at the scrap site has pulled some cards and at least in one case a chip fom a card. There is to much missing to rescue this computer..at least my friend has saved some of the pcb's: hier die HP-Kartennummern: 12103-60004 1MB RAM , 2x vorhanden 12005-60012 Ser. Interface 12005-60001 Ser. Interface 02430-60009 drop me a mail if you are interested on buying those cards and give a hint what you want to pay for them. The stuff is located in Weimar, Germany ..Europe. Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Straße 42, 09600 Oberschöna, USt-Id: DE253710583 i...@tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741
