test-drb May 2021

test-drb@ccmp.vtda.org

128 participants
102 discussions

by paulkoning＠comcast.net

> On May 23, 2021, at 5:18 PM, Wayne S <wayne.sudol at hotmail.com> wrote: > > ISTR That the 2 main issues hindering wide spread adoption of TR was cost and and not knowing where TR development was headed. > The Type 1 cabling needed to each port on the hub was expensive vs thick/thin Ethernet with taps (as were the hubs). Also, there was no second source for TR chips so everyone who wanted to make TR hardware was at the mercy of the IBM chip pricing so there weren?t too many TR cards being manufactured by anyone other than IBM. I recall the Madge TR cards for IBM ps/2 machines being about $400 ea circa 1992. > So you had a lot of cost standing in the way if you were thinking about going/staying with TR and had hundreds of workstations. There was also the bogus addressing and strange bridging. > As for development, there was an ethernet roadmap ( don?t remember the group that put it together) stating that 100 mbit was next running over shielded twisted pair then unshielded tp. And 1000 mbit was possible. > For TR, No one knew if IBM would up the speed past 16 mb and allow TR chips to be made cheaply. > > Also the fact that token passing is inherently slower than CSMA/CD did not help to sell TR. > The analogy was that if you had a long street with many stop lights, using TR would be like having every light be red and having to stop at each light, where using Ethernet some of the lights would be green and no stop required. > > IBM tried to use that to their advantage and use to say since the amount of time it takes to token pass could be measured precisely that the network response as a whole could be determined and capacity planning was more deterministic using TR than Ethernet. While at DEC in the network architecture group I contributed to a DEC marketing document that was a detailed point by point reply to an IBM document. IBM tried to claim TR was superior, we demolished that in detail. The deterministic argument was in there; unfortunately for IBM it is true that the network is deterministic -- has an upper bound on transmit latency -- but that upper bound is so crazy large that the property has no practical value whatsoever. BTW, this is where FDDI is vastly better, since it uses 802.4 timed token protocol rather than 802.5 token passing. paul

3 years, 7 months

RS64 on a PDP-8?

by jnc＠mercury.lcs.mit.edu

> Is there a controller to attach an RS64 disk to a PDP-8? The only > controller for the RS64 I can find is the UNIBUS RC11. Thanks. I never saw any reply, so I gather the answer is 'no'. I looked through the stuff on BitSavers for a bunch of other machines (IIRC, PDP-9 and PDP-12 and maybe one more), didn't see anything. The odd thing is that based on the RS64 manual cover/format, it dates to the same time period as the early -11's; and that manual is very careful to separate the drive info from the controller. Very strange that it wasn't interfaced to something else (like an -8 or -9). Maybe there was at one point a plan to do so, but plans changed? I note that there is an RS32 - I onder if they are any relation? Noel

3 years, 7 months

VAXstation 4000/90 Diagnostics

by healyzh＠avanthar.com

Is anyone familiar with the 4000/90 diagnostics? It looks like it will fail the test of the LCSPX graphics board, if it?s not plugged into a monitor, or is missing a loopback device. Is that correct? T 2 fails, but the manual makes it sound like I need a loopback T 100 succeeds when testing the LCSPX graphics board. The system had been a boat anchor until a short time ago, as the battery in the Dallas DS1287A RTC was dead. Amazon just delivered two DS12887?s. Once I replaced it, it came right up. I was surprised to see I had a 4GB and a 2GB drive in it. Now to dig out the mouse, and wait for the parts to hook it up to a monitor. :-) Zane

3 years, 7 months

SCSI2SD

by healyzh＠avanthar.com

Does anyone have experience using a SCSI2SD board to replace a Hard Drive on a VAXstation or an AlphaStation? I?m thinking about using them on some of my systems to reduce the amount of noise. I?ve gotten used to a quiet office. :-) Zane

3 years, 7 months

COMPAQ ISA PC to ethernent

by cctalk＠gtaylor.tnetconsulting.net

On 5/23/21 10:35 AM, Warner Losh wrote: > I'm out in Brighton:) Has it been wet there for you too for the last ~36 hours? Are you suggesting splitzies on Rich's collection? Or is that a veiled threat / invitation to share a beverage and chat? ;-) -- Grant. . . . unix || die

3 years, 7 months

SCSI2SD

by cruff＠ruffspot.net

I've also used a version 5.1 SCSI2SD on a VAXstation 4000/60 without problem.

3 years, 7 months

SCSI2SD

by mark＠matlockfamily.com

> <healyzh at avanthar.com> wrote: In this the weakest link would appear to be the SD Card. As such it seems to me that the best solution would be to have 2 or more SCSI2SD?s in the device. I?m not sure what benefit would be achieved by using a single board to present multiple devices. Unless of course you had a drive size limitation, or you?re trying to emulate something like 2GB or 4GB drives. As an example, that would be handy for VAXen with a 1GB Boot Drive limitation. -Zane Zane, I am using SCSI2SD cards in a VAXstation 4000/90a, and in a MV3100-80 as well as an Alpha DS10. In the two VAXes, I use two SCSI2SD cards, configured identically with a system drive and a user drive on class 10 16GB microSD cards. So each microSD card has both the system drive and the user drive. Thus I can use VMS backup from one microSD card to another so that if one microSD card fails I can easily recover from it. So far I have not had hardware failures, but being able to recover from a bad software installation which has been VERY helpful. Mark

3 years, 7 months

VT100 dot stretching in reverse video

by lars＠nocrew.org

Hello, Is there anyone with a VT100 (or any VT1xx, if so please specify which) that can make a photo displaying text in reverse video? I'm making a detailed simulation of the VT100 hardware, and I'd like to see what, if any, effect dot streching has. I searched the "VT100 Technical Manual", but as far as I can see it doesn't say. A good sample text would be: ESC [ 7 m b d h x CR LF ESC [ 0 m b d h x CR LF

3 years, 7 months

PDP-8/e M8652 KL8F Double-buffered asynch terminal control

by ccth6600＠gmail.com

I am looking for the manual for the following Omnibus board: M8652 KL8F Double-buffered asynch terminal control Is there a scanned copy of the manual and/or schematic or any other information for this board somewhere? Thanks and best regards Tom Hunter

3 years, 7 months

DEC DUP

by aek＠bitsavers.org

posting this over here, if anyone has any clues for this guy i could dig in the DEC archive but it won't be any fun to find https://www.vcfed.org/forum/forum/genres/dec/1209678-documentation-for-dec-…

3 years, 7 months

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test-drb May 2021