test-drb September 2006

test-drb@ccmp.vtda.org

200 participants
374 discussions

by ajp166＠bellatlantic.net

> >Subject: RE: CompuPro floppy controller differences > From: "Chuck Guzis" <cclist at sydex.com> > Date: Mon, 18 Sep 2006 09:22:52 -0700 > To: cctalk at classiccmp.org > >On 9/18/2006 at 8:06 AM Allison wrote: > >>3.5" 720k > >There were two "standard" versions of the 720K 3.5 format, differing in the >cluster and FAT size. One was the definition put out by IBM sometime >around MS-DOS 2.1 and the other, by Microsoft in MS-DOS 4.00 (which was an >abomination). > >So, you haven't used 3.5" 1.3MB DOS diskettes? (2x8x1024)? Many USB >floppies and Superdrives support the DOS-V format under Windows 2K and XP; >though FORMAT doesn't appear to understand how to initializae blanks. > >...and let's not forget the short-lived "special" distribution formats from >IBM and Microsoft that got around 1.8MB per 3.5" floppy by using more >sectors per track+interleave+skew(MS DMF) or differing sector sizes (IBM >XDF). I suppose you could call those "standard", since they were >officially-endorsed formats. > Just goes to prove PCs and what standards. ;) They were all over the map just like all the other boxen on storage. Allison

19 years

OT: Stepdown convertor

by aliensrcooluk＠yahoo.co.uk

Hi, I have been having problems with my Dreamcast (that I use to surf the 'net) resetting randomly. After checking out the power lines, it seems that the stepdown convertor is at fault. It has a crack and 2 bulging bits (where the plastic has been molded with lumps instead of flat) on the underside. How dangerous is this if it is the cause of the problem? It converts a 240V input to a 110V output (not been able to check the exact specs on it, as it's in use and very hot), as my Dreamcast I am using is a Japanese model (my UK model isn't fully functioning). Reply to me directly if you believe it isn't of interest to the other listmembers. I have just been on eBay to get a replacement. Regards, Andrew B aliensrcooluk at yahoo.co.uk

19 years

SCSI CD burner

by technobug＠comcast.net

On Mon, 18 Sep 2006 13:58:47 -0500, John Foust <jfoust at threedee.com> wrote: > At 02:35 PM 9/16/2006, CRC wrote: >> The basic problem with commercial CD burners/players is that they >> keep the laser diodes on when powered, although at the low power >> required for reading. The life of run-of-the-mill laser diodes is on >> the order of 10,000 (10.000) hours. Consequently, if you keep your >> system on all the time you can expect one to two years of useful life >> from the beast (some longer, some shorter). From <http:// >> www.wtec.org/ loyola/opto/ad_rohm.htm>: > > That document dates from 1994. You'd think that manufacturers would > want to increase MTBF and eliminate failures as quickly as possible, > so I find it hard to believe that LEDs are left on inside today's > CD/DVDs just because it's hard to turn them off and they don't want > to improve lifetimes. This info may be entirely relevant for > 1980s drives, who knows? My intent was to address classic computer equipment. MTBFs of Laser Diodes (LDs - not LEDs) has definitely increased over the last 10 years. However, access to information of the ones used in current CD equipment is privy only to large scale manufacturers. Looking at LDs that are used in fiber optic transmission shows a substantial increase in MTBF over the past 10 years. However, I would hold off on buying into the BlueRay recorders - blue LDs are still have low MTBFs. CD equipment production has progressed to commodity class and every penny represents a margin change of $10k / 1M units - design is done by taking out things until the unit doesn't work :=)). Adding the circuitry to turn off the laser is not difficult, but it costs money... > What sorts of other ancedotes and > claimed facts do we have? > > From the CD-R FAQ: http://www.cdrfaq.org/faq05.html > > Subject: [5-2] How long do CD recorders last? (1998/04/06) > > The MTBF (Mean Time Between Failures) on these drives is > typically 50,000 > to 100,000 hours, and they come with a 1 year warranty. Compare > that to > hard drives rated at between 500,000 and 1,000,000 hours with a 3 > or 5 > year warranty and that should give you some idea. Most of the drives > available today weren't meant for mass production of CD-Rs. The only > exceptions are the venerable Philips CDD 522, Kodak PCD 600, and > Sony CDW-900E. > I assume that the FAQ uses manufacturers stated MTBF - there is no citation for their source. > By 2004, MTBF for consumer CD/DVD were up to 60K to 100K hours: > > http://www.computingondemand.com/reviews/storage-LiteOn-LDW-411S/ > page1.shtml > > And perhaps their MTBF was calculated with a 2% duty cycle, which > would still mean they expect a consumer DVD-R to be able to burn > several thousand discs. I suspect consumer losses are due more to > dust and crud on discs... unless of course you simply don't want to > trust manufacturer-provided MTBFs. In most cases, the criteria for the MTBF is not stated as indicated by your suposition. One has to look at MTBF at temperature since Optek shows a factor of greater than 25 in MTBF between 25 and 70 C. If the tests were run at 20C and you run the device at 50C you can expect 6K and 9K hours vs 70K and 100K hours respectively (based on ratios from the Optek MTBF data for their OPV200 series high reliability LDs). At 70C it's around 1.5K and 2K hours. It's not that I don't trust the manufacturer, it's just that there is insufficient info and the manufacturer's shills will present their most favorable data. Besides the mechanical/electrical failures, which there are many, the LDs power loss generally results in the inability to record and read reliably. Note that the LD does not touch the disk and unless it is used in a smoky/cruddy atmosphere there should be no failure in the optical link. In trying to repair a good number of CDR/W I have recovered only several units by cleaning the LD lens. Recording generally uses virgin disks and an occasional brushing of the lens does help. > > Your average $50 Wal-Mart DVD drive has a 70K MTBF: > > http://www.liteon.com/prod/getProduct.do? > cid=1_7_13&xml_id=4_2&menu_id=4_2_7 Note that the stated MTBF is in POH - power on hours - not usage hours. I guess if you use it all bets are off :=P CRC

19 years

Bet you didn't know...(PDP-11)

by fireflyst＠earthlink.net

As of September 30, 2006, the last PDP-11 that rolled off the line will finally be 10 years old. The PDP-11 EOL was actually September 30,1996. As an interesting tidbit, the life span of the PDP-11 still has the PC beat by two years at this point in time. Here's to many more years of enjoyable service...

19 years

ATT 3b2 mouse

by ken＠seefried.com

> From: David Griffith <dgriffi at cs.csubak.edu> > > Does anyone know what sort of interface the AT&T 3b2 uses for its mouse? > I found one which is missing its mouse. > I've never seen a 3b2 with a graphics display. While I've seen an awful lot of 3b2s (AT&T carpet bombed Gatech with them in the mid-80s), that doesn't mean there wasn't one. Do you perhaps mean the AT&T Blit family of graphics terminals (Jerq/Blit/5620/630/730) that were often serially attached to 3b2s? If so, http://www.brouhaha.com/~eric/retrocomputing/att/5620/5620_faq.html should be a start, as well as any surviving archive of comp.terminals.tty5620. These things are nifty. Ken

19 years

C64 ASM Question

by healyzh＠aracnet.com

Now for what is no doubt a very stupid question that I'm hoping someone can help with. I'm using "Turbo Macro Assembler '05", and have verified that it works with the following simple little program that I got off the web: * = $1000 loop: inc $d020 ; increment $d020 jmp loop ; jump to label loop I can get <-- 3 "Assemble and run" to work just fine, however while <-- 5 "Assemble to disk" seems to work, how on earth do I execute the program that is created? Obviously I need to do a: LOAD"FLASH",8,1 It loads just fine, and I assume I need a SYS statement with an address to start it, but what on earth should that address be? Zane -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com (primary) | OpenVMS Enthusiast | | MONK::HEALYZH (DECnet) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | PDP-10 Emulation and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |

19 years

CompuPro floppy controller differences

by ajp166＠bellatlantic.net

> >Subject: RE: CompuPro floppy controller differences > From: Fred Cisin <cisin at xenosoft.com> > Date: Mon, 18 Sep 2006 17:51:43 -0700 (PDT) > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On Mon, 18 Sep 2006, Chuck Guzis wrote: >> You've forgotten the original DOS 1.x 160K SS and 320K DS. I wonder if the >> conservative 8-sector approach on the part of IBM/Microsoft was the >> miserable track record of the original (IIRC, Shugart) drives. The one >While there might be regional variations, I NEVER saw IBM use a >Shugart in the 5150. For the first year or so, it seems like they were >all Tandon TM100-1, and later IBM contracted to have drives made with IBM >front panels by CDC? and others. Likely because every working SA400 (400L) I have has been repaired or lightly used, lousy track record for reliability. >But not Shugart. OTOH, TRS80 and Apple][ both used Shugart mechanisms >(SA400 for TRS80, SA390?? for Apple(with Apple's own board on them)) >Most of the early Shugart SA400s were 35 track, instead of 40. By 1980 the SA400 was always the SA400L 40 track version. One issue of the time was shortages of TTL ICs and disk drive getting scarce due to demand. Allison

19 years

CompuPro floppy controller differences

by ajp166＠bellatlantic.net

> >Subject: Re: CompuPro floppy controller differences > From: Patrick Finnegan <pat at computer-refuge.org> > Date: Sun, 17 Sep 2006 12:42:54 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On Saturday 16 September 2006 16:30, Allison wrote: >> >As much as I dislike PeeCees, at least they have the benefit of >> >standardization. >> >> Ah, it's using the definitive PC FDC. It was developed well before >> PCs standardized. PCs however don't offer much choice and if they did >> keep all the FDC features you could put a 8" on a PC and read SSSD! > >I actually *can* do that on a K6-2 box I've got sitting at work (and >have done it several times). I have a few that can too, so much for standard. ;) Allison

19 years

Arcade Trackballs (was: Re: C64 Fuse?) (REPOST)

by compoobah＠valleyimplants.com

Regarding the patents: it is likely that what is being talked about is not the general "trackball" patent but a specific technique of ruggedizing a trackball for hostile situations. That would be my read, anyway. Scott

19 years

IRIS update / interesting Mac II/x/fx failure mode (REPOST)

by compoobah＠valleyimplants.com

Well, had a marathon evening over at Bear's place a week and a bit ago - brought over the disks from my ailing IRIS to see what we could scavenge. They had GL2-W2.5 on one disk, and assorted projects on the other (looks like this was one of the machines that Virginia Tech had (what was it's journey over here, I wonder...) and tried to port X11R5 to IRIS graphics on. (doesn't seem to have worked). Short answer - PSU seems OK, likely just noise from the improvised scope probes. Bad news: the pin headers on these beasts seem to be getting fragile. Bear's went out with the same symptoms (no memory seen, no graphics) after we tried a boardswap (to verify general functionality of a boardset, not to fix anything). If you have one of these beasts, pull your PSU apart and replace the 4 green paper caps on 2 boards (2 caps per board, one board is the 5v welder output, the other is the main chopper). They seem to be on their last legs, this is the second machine I've seen that suffered an olfactory capacitor failure. And the Mac stuff- IIs, IIxes and, perhaps, IIfxes have canned electrolytics on their logic boards that leak. This effluvium has, on two occasions that I have verified, eaten through the board trace that links the power-on circuitry to the power-on switch and keyboard port (one II, one IIx). If you have one of these machines, you might want to check your boards and clean them if they show signs of leakage. If you have a beast that will not power-on, I can point you where to look... it was the same area on both machines. No word yet if it messed with any of the other traces.

19 years

← Newer
1
...
13
14
15
16
17
18
19
...
38
Older →

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb September 2006