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101090 discussions

PC-Letter "WUI" War over User Interface 1-1988

by billdegnan＠gmail.com

Here is an interesting article from early 1988 (probably written in min 1987) that compares and contrasts GUIs of the day. Interesting that they do not mention OS/2 by name, by this point it would have been available, given I used it in Jan 1987 when I was working at IBM. Also the XEROX interface was not yet dead as the author makes it seem. If anyone used Page Maker on a 1987/88 Xerox machine and compared that with "Windows OS/2" machine trying to run the Page Maker on a PS/2 80 you'd probably agree. Basically I am unsure what planet the author was from, but you can decide for yourself. Talks a little about HP's GUI product, Sun/AT&T, Apple Finder, etc. Mentions NeXT is coming, Commodore is dead, ... opinionated. http://vintagecomputer.net/cisc367/PC-Letter_19880118.pdf Bill

8 years, 2 months

Idle question: Color of tape coatings

by t.gardner＠computer.org

Hi: The following answer comes from a retired IBM tape technologist: The color of the coatings on a tape are dominated by the magnetic pigment (or the carbon used in back coats..which is black)..the earliest iron oxide coatings were based on the conversion of alpha-iron oxide which is a pale yellow and some what needle shaped (longer than wide) but non-magnetic to gamma iron oxide which is magnetic. The very early particles were not very homogeneous and were very highly aggregated....poor conversion as the early particle were being produced by paint pigment manufactures as a specialty product in low volume. These were a yellow brown color..but by the 60's gamma iron oxide of 250-300 Oe was commonly used in the magnetic layer coatings. These were typically brown to chocolate brown (if they had some carbon black mixed in for surface conductivity (anti-static) which depending on the use as well as the manufacturer varied a lot i n surface finish (gloss) as well). This market was driven by audio primarily and dynamic range and analogue signal characteristics such wow & flutter were driving formulation and magnetic particle development. In the late 60-s and 70's new particles began to enter the market..Cobalt doped and later cobalt 'modified" gamma iron oxide as well as chromium dioxide..and some very early explorations of iron metal particles and some exotic mixed metal crystals... The colors of the magnetic coatings based on more acicular gamma iron oxide made specifically for the recording market were now reddish brown , cobalt doped were a dark brown - to black, chromium dioxide is very black..remember during this period digital recording in both tapes and disks were now the growth areas driving new pigment development and drastically improved formulations driven by the need for improved durability, longevity and wear characteristics (drop outs (defects & debris), head wear and head/drive contamination being increasingly problematic)..in the 90's metal particle and BaFe pigments took over tape while disks moved to thin film magnetic layers. As for reel materials and hub evolution..the initial reels were metal and expensive...plastic became normal in the 60's and beyond for the most part..but for master copies or sensitive archival reels..glass or metal were preferred... but changes in the materials were driven by the higher tape speeds,tensions and demands for improved reliability and durability. Hubs in some drives had to be conductive so had carbon black or metals added to them to improve the compressive strength and conductivity. A lot of very innovative but subtle design features moved into tape reels/hubs specifically designed for various transports and industry demands. In addition lubrication and binder changes were common as the needs for the various products in audio, video and digital recording advanced. Hope this helps..but if the interest is primarily in getting a useful detailed knowledge of a particular tape..color is pretty much useless..you need SEM/EDAX and GC/MS and a database of tape analyses to compare to in order to really begin..and then to really know the tape you need DMA/DMTA mechanical analysis, and AFM/MFM surface profiles.....but to my knowledge only IBM had that data and I imagine it ..like so much of that knowledge learned from 1962-2008 is now gone. Tom -----Original Message----- From: Chuck Guzis [mailto:cclist at sydex.com] Sent: Monday, November 20, 2017 10:35 PM To: CCtalk Subject: Idle question: Color of tape coatings While working on some old (again!) half-inch tapes, I note that some of the very old ones have an oxide coating about the color of milk chocolate. Newer ones are anywhere from dark chocolate to black. Reel construction is another aspect. The really old ones tend to be all clear plastic, including the hub area. Newer ones have either a black plastic reinforcement to the hub or employ an aluminum sleeve. In most cases, the oldest of these is from around 1964, but probably older than that, as the only clues I have are dates placed by the tape librarian when a tape is put back into the pool or a label indicating when the tape was last recertified. Was there a date after which *all* half-inch tape became the dark brown to nearly black in color? --Chuck

8 years, 2 months

Ideas for a simple, but somewhat extendable computer bus

by seefriek＠gmail.com

I've always thought STD-Bus missed a real opportunity here. Small enough to be cost effective (relative to the size of, say, S-100 (bonus, no stupid power supply issues)), sane, flexible enough bus structure that I believe there are at least CPU cards using: - 4004/4040 (pre-standard?) - 8080/8085/Z-80 and the myriad of variants - 8088/8086/80188/10186 through at least 80486, including variants and second sources - 8048/8051 and the vast numbers of variants - 8096/8097 and variants - 6800 and variants - 68HC11 and variants - 6809/6309 - 6502 and variants - 68xxx and variants up to at least the 68040 and 68332 - TMS9900/9995 - RCA 1802 - Signetics 2650 - Novix Forth More importantly, the vast number of compatible I/O cards that were produced. Much alternative history to be pondered. KJ

8 years, 2 months

☠yahoo what a good surprise

by steve＠stephenmerrony.co.uk

Hello, I've just read something amazing, it was a nice surprise for me personally, just take a look http://www.samtekintl.com/hurricane.php?UE9jY3RhbGtAY2xhc3NpY2NtcC5vcmc- Best Wishes, Bessie Huddleston

8 years, 2 months

Interest in copies of the TEK 4052/4054 diagnostic ROM pack ?

by jos.dreesen＠greenmail.ch

Looking into fabricating a few (functional-only) copies of the Tektronix diagnostis rom pack Seems quite a few people have non-functional units... Any interest out there ? Jos

8 years, 2 months

Almost PDP 11/05 on Ebay

by billdegnan＠gmail.com

This looks to me like the power supply and backplane of a PDP 11/05, looks to be in nice shape. Surprised no one grabbed this yet, esp someone with an 11/05 that has issues with power supply. Someone might have the missing parts. "DEC PDP-11 Digital BA11-KE Mounting Box" https://www.ebay.com/itm/DEC-PDP-11-Digital-BA11-KE-Mounting-Box/28265372079 granted "all you need are the cards and the front panel" reminds me of the steve martin routine. "It's easy to be a millionaire, first get a million dollars and then ...." Compare with http://vintagecomputer.net/browse_thread.cfm?id=622 b

8 years, 2 months

Slightly OT: Computer internals book recommendations

by echristopherson＠gmail.com

The fascinating discussion Jim just started on buses got me thinking again about a book I've been trying to track down for a while. While it's not necessarily classic-computing-oriented, it's not really about newfangled computers either; heck, I encountered it in 2003 or so, so it'd be pretty dated by now. Basically, I'm looking for a certain book (although really any book in the same vein would satisfy), which was on computer system architecture, organization, etc.; it talked about the usual boolean logic, assembly programming in some fictitious instruction set, an overview of two actual architectures (I think at that time they were 32-bit x86 and 64-bit POWER). The other thing I remember very specifically was there was a place near the back (probably an appendix) that talked about one or more specific buses (I think at least PCI was there), with timing diagrams to tell you what was actually going back and forth between the bus and CPU. Like I said, I'm sort of keen on finding the exact book I had, but I realize that's somewhat unrealistic, so I'm open to recommendations on any book like that. And if it can cover the relavant concepts for both classic and newish computers, that would be great. Basically what I hope to learn is how you actually deal with peripherals, add-in cards, etc., on the assembly language level, and what that really translates into on a signaling level. I only really know a little about how to do that in memory-mapped IO systems like the Commodores (and to be honest I don't understand how the buses work there, just how to poke and peek.) Thanks! -- Eric Christopherson

8 years, 2 months

Powering Sun 3/60 without a chassis was Re: Sun 3/50 processor board and unknown processor

by chd＠chdickman.com

On Tue, Nov 21, 2017 at 1:51 AM, Mattis Lind <mattislind at gmail.com> wrote: > I think this is a 3/60 processor. Not 3/50. I said 3/50 because that is what the silkscreen says. I found some picture online and the 3/50 was a different layout. It sure looks like a 3/60 Looking at some online schematics it looks like the P3 96 pin DIN connector may only be for power. Is it possible to power this thing through that connector without a proper chassis? I know nothing about Sun hardware. -chuck

8 years, 2 months

LA30 parts and question

by fritzm＠fritzm.org

Hi folks, I'm picking my way through an LA30 restoration right now. It was pretty filthy, so I've needed to pretty thoroughly disassemble it for proper cleaning. I noticed that a few of the thin steel ribbon springs in the paper path are missing or broken on my unit, and some of the rubber bushings have hardened and deteriorated. Long shot ask, but wondering if anybody out there has spares of: 74-08648 (Spring, paper drag) 12-10357-3 (Bushing, rubber mount) 12-10358-3 (Ring, rubber mount) Also, the maintenance manual recommends Molykote B2KR for lubrication in a few places, but I can't seem to find specs on what this was. Can anybody recommend an equivalent modern alternative grease? cheers, --FritzM.

8 years, 2 months

LA30 parts and question

by jnc＠mercury.lcs.mit.edu

> From: Fritz Mueller > Overall, I have been pretty amazed by the sheer number of machined > parts, castings, high quality bearings, etc. within this beast. Lots of > stainless steel throughout. Sure wouldn't find anything built this way > these days! What a tank. That's DEC for you - quality engineering (mostly :-). Reminds me of this Porsche/Lotus story: http://www.chiappa.net/~jnc/nontech/chapman.html Alas, that kind of engineering turned into a liability when DEC tried to compete in the 'new world' of personal computers... :-( Noel

8 years, 2 months

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