test-drb

test-drb@ccmp.vtda.org

101090 discussions

by ajp166＠bellatlantic.net

> >Subject: Re: Drum vs. Core > From: Kevin Handy <kth at srv.net> > Date: Mon, 02 Jul 2007 14:04:24 -0600 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > >Chuck Guzis wrote: >> On 2 Jul 2007 at 19:51, Roger Holmes wrote: >> >> >>>>> That processor benchmarks about the same as an IBM PC/AT (!) >>>>> >>>> [somehow I cannot see running 100 terminals off an AT] >>>> >>> Was it really that slow! We really put up with a lot back then. >>> >> >> Terminal speed can mask a lot. How many ASR33's did IIT run IITRAN >> to using what, a 16K foreground partition on a 128K 360/40 running >> DOS? >> >A lot of the increased speed has been eaten up by the >Graphical Interfaces. Consider that most home >PC's today operate faster and have more memory than a >Cray-1, and can barely keep up with e-mail. > >We used to have 30+ users on a PDP-11 with max 4Mb >memory, and now dedicate a Dual Core system with more >than a Gb to a single web surfer. And using an 8 core CPU >machine (PS3), just to play games. > >How large would a PDP-10 system have been that had >anywhere close to the disk/ram/... of a single PlayStation3? >Technology has really shrunk things down. The BOCES LIRCS system (LINY Ca1970) was a PDP-10 running tops-10 64kW then later 128W of core with a 128K swapping drum. Number of users on an average day was 300 (TTYs) with a PDP-8i handling switching and a few other tasks. Disks were four of the removable multiplatter washing machines (RP03) three active and the fouth holding the backup pack. It was a very reponsive machine unless there was contention for the disks (reads/writes). It's size in an airconditioned false floor room was 5 "racks" wide for the back row (mostly core boxes) and the front row was CPU, and PDP-8. Spent better part of a year there as a student just hacking on the machine like most fo the other students that had access with one little difference, I was hacking via a Hazeltine 1200 glass TTY and had access to the programmers console and tty(asr35). Allison

18 years, 11 months

RiscOS hardware in the US?

by aek＠bitsavers.org

> Are you talking about RISC/os, the SysV/BSD hybrid sold by MIPS No, this is a ROM-based operating system sold with Acorn RISC personal computers.

18 years, 11 months

Drum vs. Core

by roger.holmes＠microspot.co.uk

On 2 Jul, 2007, at 18:02, cctalk-request at classiccmp.org wrote: >> When I was at university (71-74), the college's mainframe >> still used a drum from program overlays (probably really the virtual >> memory backing storage, but possibly just dumping and restoring the >> whole program between time slices. The machine was no slouch, it was >> serving about a hundred terminals and running a couple of batch >> streams as well (Maximop and George 2). > > I take it that this was an ICL 1905E (probably at Swansea or QMC). Yes, QMC. It got upgraded to a 1904S whilst I was there. Maybe it was the 4S which had 100+ terminals, there was certainly a large increase whilst I was there. Initially most were printing terminals with lights inside, not Teletypes, can't remember the maker's name. There was also just two CRT terminals, on which you typed a load of lines and told the computer to read it. You could edit small programs on screen but on the priniting terminals you had to give it commands to change character and to step through your code. Later on we got Data Dynamics terminals, an acoustic box (to save the ears) around a naked ASR33 or KSR33 Teletype. Then we got the fairly standard 'glass teletypes', though by then I was mostly using the IMLAC graphics terminal. Do you think the drum got kicked out when we went over to the 4S? I never got to see the 4S. It was all hands off. All changed when I got to Marconi-Elliott Avionics, the training consisted of - there's the computer, here's how you turn the thing on, there's the mylar tape library, the bootstrap is at 8181, get on with it. > That processor benchmarks about the same as an IBM PC/AT (!) > [somehow I cannot see running 100 terminals off an AT] Was it really that slow! We really put up with a lot back then. > > Originally on the 1900 series the drum was considered a different > peripheral > type (ie needed different programming) from an Exchangeable Disk > (EDS) or > Fixed Disk (FDS), but, by the time we at City acquired Swansea's old > 1905E and drum (and some EDS30s), new Executives appeared with > UDAS (Unified Direct Access) where the drum was programmed just the > same as a disk. These Execs, unlike the previous versions, were > overlaid > (I think they were still, however, written in engineers assembler > which used > numeric op-codes rather than the mnemonics of PLAN or GIN5). Interesting. Maybe it was like my school maths teachers who forced us to use fountain pens instead of ball points because it slowed us down so we thought more about what we were doing and so made less mistakes. At Marconi, the hardware test programmers/engineers always used a different language than those of us in the utility software group, and we provided the higher level language compilers for the applications writers to use. > Each overlay was (most of) a 128 word disk sector ... tight modular > code > was rather forced! ... it also had to be position independent on a > machine > with no real architectural support for such - and you had only > minimal use > of the Datum/Limit registers in Exec mode. Very difficult. I had always assumed the executive lived at a fixed position in memory. Maybe it used relativisers, 1300 style, where every instruction could specify what block start address should be added to it, but maybe that would slow down loading the overlays too much. I wonder if any of the concepts in the 1302 executive got re- used on 1900. Obviously not the code itself, very different architectures, just sharing the 'standard interface' and the concept of the executive itself. > The drum was, I think, 512K characters (128K 24-bit words). We put the > Exec overlays and the Maximop overlay file on the drum - I'm not sure > what else. It probably was too small for the Maximop swap file. > George II > and the main compilers and consolidator (ICL's name for the link > editor) > were probably also on the drum. George had little to gain fromsuch a > location > as it did not use overlays except that job wrap-up and start > reloaded the > full code, some of which got overwritten during processing - British > operating > systems of the era tended to use a "job description" at the start > rather > than > the interspersed "control cards" typical of IBM. Right. > We got rid of the drum at the start of our transition from ICL to > Honeywell - > it took up too much space in the machine room and the Level 66 was a > BIG machine (physically). Maybe ICL had been bumping up the maintenance charges for old kit they really did not want to support any more. Keeping engineers trained up on kit for a handful of customers is not very cost effective, and the older engineers who knew the old kit keep getting 'promoted' into management.

18 years, 11 months

Free for Pickup in Phila, PA - TOPS Networking stuff

by alhartman＠yahoo.com

I have a box full of TOPS networking software and some hardware (Flash Cards for the PC, and connectors for the Mac) that I don't want to put in the dumpster. If you would like this box, and can come pick it up in Philadelphia PA.... It's yours!!! Email me off list. Al Phila, PA

18 years, 11 months

Aerco Easie-ST RAM Upgrade for Atari-ST

by alhartman＠yahoo.com

Hi all, I have one of these beasts in my Atari-ST and it's not working. I haven't been able to find the manual for it. If anyone out there has the manual, and can make a copy for me, I'd reimburse the copy fee, postage and send you something for your trouble. Or... If anyone knows any of the principals of Aerco (from Texas if I remember) who can put me in touch with one, who might have the manual would be great! Thanks!! Al Phila, PA

18 years, 11 months

Apricot F1 software needed

by classiccmp＠memory-alpha.org.uk

Hi, > Speaking of Apricots... I've got an F1 I purchased from ebay >and it came with a full set of manuals, but no software. Can >anyone help me out? I gave away almost all of my Apricot collection (and software) some time ago, however you should find something useful over at "www.actapricot.org". TTFN - Pete.

18 years, 11 months

Drum vs. Core

by roger.holmes＠microspot.co.uk

> > Core was available by 1952, most of the big machines after this > date (on this side > of the pond at least) were core based. The IBM 650 was actually one > of the smaller > machines, at least inasmuch as IBM was already making much larger > machines > (the 700 series). Wasn't core memory very expensive in the beginning? It had to be hand assembled, at least in the early days. I think there was a more gradual take up than you suggest. Of course the more expensive machines which used it first saw a huge speed increase over drum main memory. When I was at university (71-74), the college's mainframe still used a drum from program overlays (probably really the virtual memory backing storage, but possibly just dumping and restoring the whole program between time slices. The machine was no slouch, it was serving about a hundred terminals and running a couple of batch streams as well (Maximop and George 2). Mid 1970s I remember seeing a small plastic pot about the size of a 35mm film canister, which was full of about 100,000 unstrung cores, they were tiny! They were used in the Marconi-Elliott 920ATC computer and also in the early Cruise missiles and some torpedoes. Ever wondered why a British submarine used a WW2 type torpedo to sink the big Argentinian Cruiser? My theory is that they were too worried about the modern torpedoes coming back and blowing themselves up, so they used one they trusted to go where it was pointed. Hopefully 25 years on, they've sorted out the terrible guidance system. Not related, but apparently the programmers were in a quandary as to what the program should do after it had issued the order to detonate. Like the old TV series 'Waiting for God'. The first machine which ICT introduced with core memory was in 1962, though physically large, the 1300 was a medium power machine, seen more as a versatile tabulator for accounts rather than scientific work, though it had a structural frame analysis package and even PERT, though I suppose that is just up market accounting in a way. Customers did all sorts of other work on it too, helping to design 'planes and even playing music on the built in speaker. There's a wonderful program called Ghost, only a half a dozen instructions, which uses the variable length of the multiply instruction to make a ghostly sound on the speaker. Its a good test of the CPU too, and can be keyed in through the control panel if need be in a minute or so. Also has drums - each one 12000 words x 48 bits run by a 3/4 horsepower motor and occupying 2ft x 2ft x 5 ft. Compared to the 8GB SDHC card for my 12MP camera which is about an inch by an inch by a sixteenth and stores 100,000 times as much in about 1 / 500,000 times the volume. And the core store is one sixth the capacity of the drum in a greater volume.

18 years, 11 months

[Fwd: Jim Butterfield passes away]

by brain＠jbrain.com

Jim Butterfield of TPUG and PET SW fame, in case anyone is interested: -------- Original Message -------- Subject: Jim Butterfield passes away Date: Sat, 30 Jun 2007 19:51:37 -0400 From: Robert Bernardo <rbernardo at IGLOU.COM> Reply-To: COMMODORE COMPUTERS DISCUSSION <COMMODOR at LISTSERV.BUFFALO.EDU> To: COMMODOR at LISTSERV.BUFFALO.EDU --- Forwarded message --- I regret to advise the Commodore community that Jim Butterfield has passed away. Jim died at 1:30 AM on June 29 after battling cancer which infected many parts of his body. His family advises that there will not be a funeral as such but a commemoration of Jim's life is planned in the next month or two. At the moment that is all the detail that I have to report. We have all lost a truly wonderful friend and teacher. Ernie Chorny -- Jim Brain, Brain Innovations (X) brain at jbrain.com Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times! Home: http://www.jbrain.com

18 years, 11 months

Bob Rosenbloom <bobalan@sbcglobal.net>

by brad＠heeltoe.com

Bob Rosenbloom wrote: > >5. DEC RA81 disc drive, with cables. > >6. DEC RL02 cartridge drive, this one may be for parts, it's missing the >door latch parts, > but otherwise looks complete. > >7. DEC PDP/11-44 computer. This has the following boards and came with >the RA81 drive: Just curious, where are you located? (I'm on the east coast) -brad

18 years, 11 months

VTL Listing Altair 680

by grant＠stockly.com

I just typed up the listing for VTL but I'm missing a few lines. I need to know what line #179, #239, and #529. I'd like to know the entire line. If anyone has access to the VTL manual I would love to get the missing lines. : ) I will provide the EPROM set to anyone interested for cost. This is what I have so far. There are probably some mistakes but I can't ever finish without the missing lines. Grant FC00: 8E 00 F1 4F CE FE FB 8D 42 4F 97 4A 97 4B BD FE | GS FC10: A3 24 3B 8D 24 27 E9 8D 65 27 E5 EE 00 DF 4A DE | GS FC20: 42 08 08 08 8D 13 27 0D DE 42 EE 00 9C 4A 27 05 | GS FC30: 08 DF 46 20 E2 8D 5A 20 E0 DF 72 BD FD EC 08 A6 | GS FC40: 00 8D 03 DE 4A 39 81 22 26 4E 08 7E FD 75 DF 74 | GS FC50: 97 4A D7 4B DE 4A 26 69 CE 01 08 9C 50 27 BA DF | GS FC60: 42 A6 00 E6 01 BD FD 20 DE 42 08 08 BD FD 58 BD | GS FC70: FE F2 20 E7 DE 42 08 08 6D 00 26 FB 08 39 CE 01 | GS FC80: 08 DF 42 9C 50 27 10 A6 01 90 4B A6 00 92 4A 24 | GS FC90: 04 20 EC 86 FF 39 BD FD 80 37 36 DE 72 BD | GS FCA0: FD FF 32 C1 24 26 04 33 7E FF 81 C0 3F 27 70 5C | GS FCB0: 33 26 01 3F A7 00 E7 01 DB 52 99 53 97 52 D7 53 | GS FCC0: 39 8D BB 27 18 EE 00 9C 4A 26 12 8D A7 9E 42 9C | GS FCD0: 50 27 08 A6 00 36 08 31 31 20 F4 9F 50 DE 74 C6 | GS FCE0: 03 6D 00 27 31 5C 08 6D 00 26 FA 4F DB 51 99 50 | GS FCF0: 97 3C D7 3D D0 59 92 58 24 22 DE 50 9E 3C 9F 50 | GS FD00: 08 09 E6 00 37 9C 42 26 F8 9E 4A AF 00 9E 74 34 | GS FD10: 08 33 E7 01 26 FA 83 00 F1 7E FC 09 7E FC 00 33 | GS FD20: CE 00 82 DF 6C CE FE 5B DF 6E EE 00 DF 70 CE 00 | GS FD30: 70 BD FE 65 36 DE 6C 96 69 8B 30 A7 00 08 DF 6C | GS FD40: DE 6E 32 08 08 6D 01 26 DF CE 00 81 63 05 03 E6 | GS FD50: 00 C1 30 27 F9 73 00 86 4F 97 87 E6 00 08 D1 87 | GS FD60: 27 05 BD FF 81 20 F4 BD FF 24 24 5B 8D 04 C1 03 | GS FD70: 27 AA 7E FF 00 8D E2 A6 00 81 3B 27 5D 7E FE F2 | GS FD80: 8D 46 36 A6 00 27 02 81 29 32 27 4E 8D 04 DE 64 | GS FD90: 20 F0 36 37 A6 00 36 03 8D 2E 97 6A D7 6B DF 64 | GS FDA0: CE 00 6A 32 33 81 2A 26 6E 32 97 68 D7 69 69 10 | GS FDB0: D7 66 4F 5F 74 00 68 76 00 69 24 02 8D 5E 68 01 | GS FDC0: 69 00 7A 00 66 26 ED 39 BD FE A5 24 0E C1 EF 26 | GS FDD0: 0B DF 76 BD FE D6 8D A8 DE 76 08 39 C1 24 26 05 | GS FDE0: 8D 90 4F 08 39 C1 28 26 03 08 20 94 8D 11 A6 00 | GS FDF0: E6 01 DE 70 39 8D 89 58 49 DB 51 99 50 20 0E 36 | GS FE00: 00 08 37 C1 3A 27 EE 4F C4 3F CB 02 58 DF 70 97 | GS FE10: 6C D7 6D DE 6C 33 39 81 2B 26 06 32 EB 01 A9 00 | GS FE20: 39 81 2D 26 06 32 E0 01 A2 00 39 81 2F 26 0C 32 | GS FE30: 8D 33 97 4E D7 4F 96 68 D6 69 39 80 3D 26 0C 32 | GS FE40: 8D E4 26 03 5D 27 02 C6 FF 20 0D 4A 32 27 07 8D | GS FE50: D5 59 4F C4 01 39 8D F7 53 20 F7 27 10 03 E8 00 | GS FE60: 64 00 0A 00 01 7F 00 66 7C 00 66 63 01 69 00 24 | GS FE70: F7 66 00 66 01 7F 00 68 7F 00 69 8D A9 24 04 8D | GS FE80: 9B 0C 9C 0D 79 00 69 79 00 68 7A 00 66 27 12 64 | GS FE90: 00 66 01 20 E6 E6 00 C1 3A 2A 04 C1 30 2C 02 0D | GS FEA0: 39 0C 39 8D 31 8D EE 25 F9 4F 5F EB 00 89 00 C0 | GS FEB0: 30 82 00*87?66*D7 67 08 37 8D DA 33 25 E3 58 49 | GS FEC0: 58 49 DB 67 99 66 58 49 20 E1 C1 40 27 06 08 8C | GS FED0: 00 4A 26 08 8D 1C CE 00 02 09 27 F8 BD FF 00 E7 | GS FEE0: 87 C1 5F 27 F4 C1 0D 28 F3 26 DF 6F 87 CE 00 33 | GS FEF0: 20 04 C6 0D 8D 02 C6 0A 7E FF 31 0D 0A 4F 4B 00 | GS

18 years, 11 months

HP FAB boards

by jwest＠classiccmp.org

Would anyone happen to have a spare FAB board or two for the 21MX/1000 boxes? One of mine is physically damaged and I'd like to keep that particular box running. I'll gladly trade or buy for one.... Jay West

18 years, 11 months

Telephony switches - is there anyone out there collecting these?

by classiccmp＠memory-alpha.org.uk

Hi, > I have a couple of the old GPO [1] Modem 2B units.... Brings back memories....the 2B was my first modem back in '85. Lots of fun, but not as convenient as one which responds to Hayes "AT" commands. I may still have some documentation somewhere if it's any use to you? TTFN - Pete.

18 years, 11 months

What are the really unusual or weird computers?

by classiccmp＠memory-alpha.org.uk

Hi, >>....The earlier assertion that it was miles away from an IBM PC >>just isn't true.... Oh, but it is....just take a look at the Apricot Technical Reference manual. > Thinking about it more, my statement about peripherals might be >stretching it. I don't *recall* any problems with 3rd party >peripherals like modems and whatnot.... Well, the Apricots had a bog standard RS232 connector and the printer interface was standard "Centronics" (though it used a female Centronics connector rather than a DB-25 as many other machines used). Also, since the thing didn't have an ISA bus, any internal expansion options would be designed specifically for the "Apricot bus" and have the appropriate drivers.... >....The F1 doesn't look like it has compatible connectors for standard IBM >PC peripherals, but ISTR that the Xi *did* have ISA slots.... No, the "F" series machines use the same "Apricot" expansion bus as the earlier PC & Xi and the later Xen series. The first Apricot machine to have an ISA bus inside was the "Xen-i", which was also Apricot's first (mostly) IBM compatible machine. >....The F1 wasn't intended to be expanded very much.... That's because the "F" series machines were primarily intended to be "home" machines. TTFN - Pete.

18 years, 11 months

Modem 13A

by ard＠p850ug1.demon.co.uk

I also came across that Modem 13A that I mentioned a few days ago, the one that's a plinth under a normal 746 telephone. The phone part is pretty normal, apart from having 2 buttons on top, in front of the handset rest, labelled 'TELE' and 'DATA'. They are interlocked so that presing one releases the other, and both are released buy the heandset rest. The 'TELE' button operates a microswitch, the connections of which go nowhere, the 'DATA' buttom operates a multi-pole changeover switch, again most of the contacts aren't used. The rest of the phone is what I'd expect in a rotary-dial 746. The base of the plinth comes off by 4 captive screws. Inside is a PCB, component side down (so you can see the components when the base is removed), also hald in by a further 4 captive screws. There are 8 wires >from the modem PCB up into the phone sectionm and a label inside the base seems to indicate that 2 of them are used to externally power the modem (it can be line-powered) -- these wires go to 2 otherwise unused terminals on a terminal strip, 4 of the wires are to be linked in 2 pairs (again done on said terminal strip) and the remaining 2 wires go to the line (presumably via that DATA switch. There are 4 terminals on the PCB that go to a cable that comes out the back. The label gives the 'CCITT circuit numbers' for each terminal, I've not looked them up yet, but they're going to be normal RS232 signals. The PCB contians a number of discrete transistors, a number of 8-lead TO99 cansm which I susepct (from the part number and connections) to be 748 op-amps and a single 14 pin DIL device, which might be something like a 7403 (???) And a lot of pot-core inductors and strange-value poiystyrene capacitors, presumably for filtering. -tony

18 years, 11 months

Tandy 2000 hack

by chrism3667＠yahoo.com

any thoughts? And although he claimed the 2000 never generated a NMI, won't a parity error always do this? Irrelevant maybe cuz that's a catastrophic fault thing, not something typically encountered... Maybe he provided more details, but I'm tired... > > I was working on a mod, never completed, for the T2K > > that would make it > > after the O/S was loaded, 100% PC-compatible. > > Required 1 hardware chip, > > and a customized IO.SYS. Whereupon any DOS > > application would run on the T2K, > > even stuff doing serial-port manipulation, direct > > video-memory writes, DMA, > > etc. The one-chip mod was a PAL that monitored the address lines from the CPU, when It saw an I/O instruction in 'low' address-space, it generated an NMI (not used at all by the T2K), then the software service routine for NMI unwound the stack to find the offending I/O instruction, and re-mapped the "PC" functionality to the T2K hardware. Coupled with a timer-tick 'refresh' routine that copied data from "PC video memory" to the T2K video memory (remapping attributes, etc. as required.) The chip actually had 2 modes of operation -- NMI active, as described above, and 'NMI inactive', where it pretty much did nothing -- except listen for the 'magic words' that made it go active, that is. :) This enable/disable mode switching was necessary, to allow "T2K DOS" internals (and/or the 'sofware service routine) to access the T2K hardware directly. ____________________________________________________________________________________ Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games. http://sims.yahoo.com/

18 years, 11 months

(no subject)

by compoobah＠valleyimplants.com

> At 09:46 AM 7/1/2007, Scott Quinn wrote: >> For a brief period, NewTek did have a Macintosh clone with a 68030 >> and system software that was a hybrid of System 6 and System 7, > > "NewTek" was an Amiga company, "NewTech" was the Mac clone company. > > - John Hmm-the reviewer in the magazine I have must have had spell-check on, as it came out "NewTek Duet" every time. Explains why I couldn't find much else on it.

18 years, 11 months

S-100 and other items looking for a new home

by w6nct＠arrl.net

Greetings, I am new to this group, so I hope that I am doing this correctly. I have a bunch of computer parts looking for a new home, many are from vintage computers. Most of the initial things I have posted are S-100 PCBs (memory, I/O, interfaces,...), many of which include documentation, and some even include software. I also have a NorthStar Horizon chassis (including linear P/S, motherboard, but no top cover or drives). There are other items as well, including a VME chassis; and I expect to have several Heathkit items posted soon. Unless specified, I believe that all of these items were operational prior to being boxed (several years ago), and still appear to be in good condition. I am enquiring with several people I have found on the Web, hoping to find one or more interested parties. I have considered posting them on eBay; but thought that I'd offer them directly first. These items are located in Southern California; so shipping outside that area may be a (minor) concern (for larger or heavier items). At the very minimum, I am interested in recovering the cost for S/H; but would prefer to get a bit more to help with my purchasing a new laptop. I have set up a temporary Yahoo Group to help with showing and describing the items; that way, it won't impact the bandwidth of sites such as this one. The Group is called "Verns_Stuff" (http://groups.yahoo.com/group/Verns_Stuff). If you have any interest in S-100, VME, or Heathkit computer items, please drop by. If you are not interested, but you are aware of other individuals or groups that might be, please feel free to forward this information on to them. Thank-you. Vern.

18 years, 11 months

What are the really unusual or weird computers?

by roger.holmes＠microspot.co.uk

> > From: "Mike Hatch" <mike.hatch at mclennan.co.uk> > >> Its got Ampex >> TM4 mag tape drives (not industry standard 7 or 9 track, these are >> ten track units with hubs the same design as professional audio >> tapes >> and the 2 and 3 inch wide video tapes once used by TV broadcasters). > > Our SDS9300 had TM4 drives but I don't remember them being 2 and 3 > inch > wide, I thought they were 0.5 inch, but then that was 35years ago. Yes they are half inch. What I meant was that they are not 'industry standard' half inch tape with large expanding hubs with the write protect ring in a groove in the reel. Instead the centres are much smaller, allowing 3200 feet on the same outside diameter spool as a 2400 foot reel using the same thickness tape (not the ultra thin tape). The reels are aluminium, not plastic, their centres have three notches which three matching 'fingers' within the hub fit into, holding the reel onto the hub. Some TM4s were fitted with small expanding hubs (the ones on the Leo and maybe others), but this did not fit 'industry standard' reels. The same design of hub is used on tapes of quarter inch, half inch, one inch, two inch and three inch, maybe other sizes too. I do not mean domestic quarter inch tape recorders, these use a simple nut on a stud. The write protect ring protrudes from the back of the reel, and three projections on the ring fit into three holes in the reel. The tapes themselves have a metalised leader which is electrically sensed by the deck. They also have a reflective early end of tape marker like later tapes, and I think they have a metalised leader at the end of tape, though I've never unreeled 3200 feet of tape to find out.

18 years, 11 months

Fwd: [acug0447] Fwd: Jim Butterfield passes away

by aliensrcooluk＠yahoo.co.uk

FYI: Regards, Andrew B aliensrcooluk at yahoo.co.uk rbernardo(at)iglou.com wrote: To: acug0447 at yahoogroups.com,auscbm at yahoogroups.com From: <rbernardo at iglou.com> Date: Sat, 30 Jun 2007 19:53:12 -0400 Subject: [acug0447] Fwd: Jim Butterfield passes away --- Forwarded message --- I regret to advise the Commodore community that Jim Butterfield has passed away. Jim died at 1:30 AM on June 29 after battling cancer which infected many parts of his body. His family advises that there will not be a funeral as such but a commemoration of Jim's life is planned in the next month or two. At the moment that is all the detail that I have to report. We have all lost a truly wonderful friend and teacher. Ernie Chorny Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/acug0447/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/acug0447/join (Yahoo! ID required) <*> To change settings via email: mailto:acug0447-digest at yahoogroups.com mailto:acug0447-fullfeatured at yahoogroups.com <*> To unsubscribe from this group, send an email to: acug0447-unsubscribe at yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/

18 years, 12 months

Drum vs. Core

by ajp166＠bellatlantic.net

> >Subject: Re: Drum vs. Core > From: "Chuck Guzis" <cclist at sydex.com> > Date: Fri, 29 Jun 2007 13:49:22 -0700 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >While the main store on the IBM 650, didn't most of the installed >base (eventually) also have 50 words of core as sort of a >"scratchpad" memory? > >Cheers, >Chuck This was common. The problem with rotating memory, mercury delay, magnostrictive delay and even shift registers is they are not random access they are sequential access They all have a fixed delay and you wait for what you want to "come around". Programmers had to program around that if speed was required. Allison

18 years, 12 months

Semi-OT: Interesting or unusual PC Compatibles?

by compoobah＠valleyimplants.com

> Now, of course, such an effort would be in violation of DMCA, but it > worked back then. I'm surprised that no one did that with the Mac > ROMs--anyone know why not? Probably because they would also then need to clone the system software as well, a much bigger task for a much smaller (potential) market. Apple would have been much less likely to deal with clone makers than Microsoft was. While the system software was made freely available in the early years, it is unlikely it would have stayed that way if clone makers had been successful. For a brief period, NewTek did have a Macintosh clone with a 68030 and system software that was a hybrid of System 6 and System 7, with a user interface based on Motif. It suffered the same problems as the 1st - gen IBM clones as far as compatibility.

18 years, 12 months

Rare Commodore 8296 on EBay?!?!?

by gmanuel＠gmconsulting.net

Is this really as rare as he thinks it is? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130128193985&ssPageName=M ERC_VI_RCRX_Pr3_PcY_BID_Stores_IT&refitem=130128166016&itemcount=3&refwidget loc=active_view_item&usedrule1=CrossSell_LogicX&refwidgettype=cross_promot_w idget Greg

18 years, 12 months

Drum vs. Core

by cc＠corti-net.de

On Fri, 29 Jun 2007, Brent Hilpert wrote: > Indeed, according to http://www.columbia.edu/acis/history/650.html there was > 60 words of core used as a buffer between the drum and tape drives to account > for their different data rates, but which could also be used for other stuff. Well, then you have to count the LGP-30 as computer with core memory, too, because the interface to the (apparently extremly rare) magnetic tape drives (yes, there were tape drives for the LGP-30!) contained core memory as buffer. The drive would buffer the block in core so that the LGP-30 could read it with its own speed (and vice versa). Christian

18 years, 12 months

stuff on ebay

by dgriffi＠cs.csubak.edu

Now that I have some more time to do it, I've listed some stuff on Ebay. My name there is "frotz661". -- David Griffith dgriffi at cs.csubak.edu A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

18 years, 12 months

imsai ram4 board

by dgriffi＠cs.csubak.edu

What sort of fun could one have with an IMSAI ram4 board? I don't think I want to sell it. -- David Griffith dgriffi at cs.csubak.edu A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

18 years, 12 months

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