test-drb June 2007

test-drb@ccmp.vtda.org

224 participants
486 discussions

by ajp166＠bellatlantic.net

> >Subject: Re: Pictures of My Machine Room (So Far) > From: Fred Cisin <cisin at xenosoft.com> > Date: Sun, 17 Jun 2007 23:11:55 -0700 (PDT) > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >> >OB_CC: Where can you get plywood that matches the Northstar Horizon? >> >The "home" stores don't even have the right thickness! > >On Sun, 17 Jun 2007, Allison wrote: >> That grade is for real carpentry not home despot wonder projects. >> The stuff used was real 3/4" finish grade with what appears to be oak >> veneer (mine is). The originals were fairly tough veneer and well >> fitted. Mitered corners and two cleats in the corner for a bit of >> stiffness. The front edge has a routed slot on the inside top and >> two sides to slide over the front pannel plate, The slot is 9/64 >> maybe 5/32" wide. Most of the early machines came with the dark >> stain wood but I'd like to find a metal one (less RFI). > >At one point Northstar was buying at Ashby Lumber, but I don't know for >sure that that was for the Horizon. > >> One of my NS* Horizon is wood cover and the other is missing the >> cover so I have a Lexan cover plate to allow airflow. > >There seem to be a LOT of missing Horizon covers! After about three to four years the glue dries out and you have a kit of cover. ;) Glue and clamps restore it nicely. Allison

17 years

T11 design WAS - Re: Inside old games machines, was: Re: Simulated CP/M-68K?

by ajp166＠bellatlantic.net

> >Subject: Re: T11 design WAS - Re: Inside old games machines,was: Re: Simulated CP/M-68K? > From: "Ethan Dicks" <ethan.dicks at gmail.com> > Date: Tue, 19 Jun 2007 10:33:29 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 6/19/07, Robert Borsuk <rborsuk at colourfull.com> wrote: >> I've been loosely following this thread and never heard of a T11 from >> DEC. So good'ole Google and Bitsavers saves the day, but it get's >> me thinking. Has anybody done any design's with this processor? > >Yes (see the thread where it appears in a few video games). DEC used >it as a PDP-11-instruction-set-compatible microcontroller. It appears >on a few peripheral boards (the RQDX3 comes to mind), and a few other >places. Falcon card (Qbus SBC), KXT-11 (programmable Qbus slave), The RQDXn (all versions) and also the HSC50. I have one of the rare design guides and a good handful of parts both ES and production. Allison > >For some real boots-on-the-ground history, we turn to Bob Supnik... > >http://simh.trailing-edge.com/semi/t11.html > >(I did not know about his T-11-based RT-11 box - I should ask him about it). > >> Why wasn't this processor used instead of the 6100? > >In what? In video games? the 6100 _might_ have been a competetive >architecture when it was new in the mid-to-late 1970s, but as >competition against an early 8-bit micro, not a 16-bit micro, which >the T-11 is. From looking at the Atari line at the time, it seems >that they were positioning the T-11 against the Motorola 68000. >Presumably there was some engineering or marketing or production >reason to go with the T-11 over the 68000, but, as much as I like the >PDP-11, I can't imagine what that would be. Perhaps the $10/unit cost >that Bob Supnik cites was favorable compared to, say, trying to go >over 8MHz on a 68000, but that's mere speculation. I know that at the >low-point in the 68000 timeline, it was going for about $3 each in >reasonable quantities, but I don't know where that curve compares to >the $10 each for the T-11. The 6100 was PDP-8 and the basic archecture is 4k addressing, 12 bit words and not rom friendly so it was not a contender for rom intensive applications. >I'm not saying you _couldn't_ make a video game based on the IM6100, >but it didn't happen to have been done, and would probably just end up >as a demonstration of engineering prowess, not something that would >have made sense from a business standpoint in 1976. Exactly! The 6120 was faster and incorperated the MEDIC (interrupt and memory expansion similar to PDP-8) but still even at 4k paged and 32k (plus 32k CP memory) it was awkward compared to most micros. Allison

17 years

NorthStar Horizon Case Cover Replacements

by ajp166＠bellatlantic.net

> >Subject: NorthStar Horizon Case Cover Replacements > From: "Andrew Lynch" <lynchaj at yahoo.com> > Date: Mon, 18 Jun 2007 17:35:13 -0400 > To: <cctech at classiccmp.org> > >Hi, > > > >I noticed in another cctech mailing list thread about the NorthStar Horizon >case cover replacements. Recently, I procured a NorthStar Horizon which is >missing its original wooden case cover and I was looking to either buy an >original replacement or make a new one. > >I did not get a lot of responses to my queries on other forums for a >replacement wooden case cover so I am considering fabricating my own. >Apparently, it is common for Horizons to have lost their wooden covers over >time for many reasons and others have done what I am considering. > >Has anyone built replacement NorthStar Horizon case covers before and would >be willing to build more? They do not look terribly sophisticated to build >provided you have access to a table saw and the proper bits. I was planning >on just copying the dimensions from another Horizon wooden case cover I >already have. > >If anyone has a spare NorthStar Horizon wooden case cover, has built new >ones, or knows how to build a replacement, I would certainly like to hear >from you. Please email me or post here. > >Thank you in advance. > First it's a simple 3 sided thing. with a groove routed (or kerf cut) to overlap the cover. The corners are mitered, grooved for biscuts and glued. I added two 1/2" cleats to the corners of mine when I reglued it. There are 4 recessed hole for screws to secure it. Nominal material is 3/4 oak ply though current dimension materials would work as well. There is nothing special about it or difficulty in making it. The metal cover is simple but without a bending brake it's not easy to do. Allison

17 years

Help on HP 82901 drive

by rbazzano＠alice.it

Hello. I have a partially defective HP 82901 drive. I found the problem on the controller card. I found a service manual on HpMuseum site, named "82901-82902_CEServiceHandbook-Partial_17pages_1982.pdf". Following it, I made all self tests and the problem is on the read circuit. I'm sure about that because the two Tandon drives work fine with another controller card. In this case, the service manual suggest to verify read oscillator frequency. Unfortunately the section VI of the manual describing the procedure is completely missing from the pdf file. Perhaps someone has this manual? I would be very gratefull if someone can help me to fix this drive. Thank you very much. Roberto

17 years

Floppy Disc Capacities [was Pictures of My Machine Room (So Far)]

by wayne.smith＠charter.net

> Date: Mon, 18 Jun 2007 22:08:44 -0700 > From: "Chuck Guzis" <cclist at sydex.com> > Subject: Re: Floppy Disc Capacities [was Pictures of My Machine Room > (So Far)] > To: "General Discussion: On-Topic and Off-Topic Posts" > <cctalk at classiccmp.org> > Message-ID: <4677026C.408.5FBF8B36 at cclist.sydex.com> > Content-Type: text/plain; charset=US-ASCII > > On 18 Jun 2007 at 21:36, Wayne Smith wrote: > > > My first iteration of Windows 95 was on 3.5 inch floppy > diskettes. At > > some point, I wanted to make a backup copy on diskettes but couldn't > > because the file sizes of the Windows distribution floppies was > > 1.8-1.9MB each. At the time I thought it was some sort of copy > > protection. I assume they must have been able to format > the discs for a > > higher capacity - close to 2MB. > > > > Does anyone know how? > > Uh-yup. Microsoft used a format they called DMF, for about 1.68MB-- > 21 sectors per track, with a very small gap between sectors. IBM had > a rather more complicated format called XDF, which used one 8K, one > 2K, one 1K and one 512 byte sector on a track for about 1.84MB. > > Handling the DMF format wasn't too hard, although if your drive was > marginal, it could create problems. The XDF actually used larger gap > sizes, but required special drivers. There was also an XDF format > for 5.25 HD that was about 1.6MB and one for 3.5 DSED which was about > 3.84MB. > > If you want to pack an amazing amount of data on a 3.5" DSHD, I > believe that there's a program for the Catweasel that will give you > something close to 4MB using a few tricks. > > Cheers, > Chuck > Cool. Great info. Thanks! -W

17 years

Atari 800XL and 1050 disk drive in Delray Beach, FL

by sellam＠vintagetech.com

Please contact Kathy for more information if you're interested: Kathy Knaack <khknaack at bellsouth.net> As far as I know it is free for the taking. -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

17 years

odd software request

by mcguire＠neurotica.com

Does anyone have any Chebyshev or Butterworth LC filter design/ analysis software in FORTRAN-II or FORTRAN-IV? (don't ask..) My google-fu is failing me on this one. -Dave -- Dave McGuire Port Charlotte, FL

17 years

manualsplus.com has 50% off all manuals right now

by aek＠bitsavers.org

Some coordination may be in order. It sounded like Richard was going to buy some Tek graphics manuals. I bought most of the orignal 85xx service manuals they had to fill in the holes on bitsavers.

17 years

manualsplus.com has 50% off all manuals right now

by legalize＠xmission.com

I just received email from the people running this business I mentioned the other day <http://www.manualsplus.com>. They are in the process of trying to sell off the business, so they are currently selling all manuals at 50% off. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

17 years

Available - DEC RX-180 AB dual 5-1/4 inch diskette floppy drive.

by tosteve＠yahoo.com

I have this DEC RX-180 AB dual 5-1/4 inch diskette floppy drive - why, I don't know. Working condition is unknown. Please make an offer if it suits you to do so. Located in southern California (OC). Paypal accepted! Thanks- Steven T. --------------------------------- Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games.

17 years

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test-drb June 2007