test-drb November 2005

test-drb@ccmp.vtda.org

255 participants
692 discussions

Start a nNew thread

PalmOS no more? :(

by bpope＠wordstock.com

http://www.cnn.com/2005/TECH/ptech/09/27/palm.microsoft.ap/index.html

18 years, 8 months

FPGA VAX update, now DIY TTL computers

by ajp166＠bellatlantic.net

> >Subject: RE: FPGA VAX update, now DIY TTL computers > From: "a.carlini at ntlworld.com" <arcarlini at iee.org> > Date: Thu, 03 Nov 2005 19:08:04 +0000 > To: "'General Discussion: On-Topic and Off-Topic Posts'" <cctalk at classiccmp.org> > >Allison wrote: > >> Parity required an extra bit to stor the parity so that it could be >> compared on read. That bit may or may not have been part of the data >> path logic. > >But on the memory chips, that bit must have been readable for the >system hardware to do its comparions. I guess that the memory could >send back a GO/NO_GO signal but supplying the parity bit must >be easier and cheaper? Actually the system does not have to see the parity bit. Only the result of comparing the stored (at write time) parity in the 9th bit with the result of the read parity hardware. If there is a difference there was a "hit". So the rest of the system gets the data and the interrupt system sees the parity if there is a fail. There is no need (in most if not all) to actually read and write the parity bit as that is a memory subsystem task (hardware). PDP-11 Qbus ram is of the case where parity is stored as a 9th bit but is not directly accessable by the CPU. In the extreme is the ECC ram where there are many bits per byte/word to store a coded form of the data (hamming or other compression) so that the ECC hardware can "repair" corrupted data. >There was a spate of "fake parity" memory around some time in >the 90s. Quite why it was cheaper to add a chip that always >supplied "correct" parity rather than simply using additional >memory was something that I never understood. But if you >end up with one these "fake parity" memories it may well >cause your 9-bit machine some issues!! If it were a real 9bitter it certainly would. In the case of PCs it was a matter of satisfying a motherboard configuration rather than real "bits". Allison

18 years, 8 months

TTL parts

by dwight＠ca2h0430.amd.com

Hi I have a bunch of what I believe are TTL parts. They all have inhouse numbers that start with 55xxx. Does anyone know what 'house' these belong to and is there a table anywhere to translate them to standard TTL names( a few do shouw both names ). These seem to be someones spare parts bins. They are all unused. Dwight

18 years, 8 months

FPGA VAX update

by ajp166＠bellatlantic.net

> >Subject: Re: FPGA VAX update > From: Paul Koning <pkoning at equallogic.com> > Date: Thu, 03 Nov 2005 11:40:57 -0500 > To: cctalk at classiccmp.org > >>>>>> "Chuck" == Chuck Guzis <cclist at sydex.com> writes: > > Chuck> On 11/3/2005 at 9:49 AM Paul Koning wrote: > >> If you're going to go the 3 address route, it sounds like you're > >> well on your way towards reinventing the CDC 6000 architecture. > >> And of course that would be a fine thing to do -- if you're going > >> to explore computer architectures, what better path to take than > >> the one first walked by the foremost computer architecture genius > >> of the 20th century? > > Chuck> ...or one could use a MIPS chip... > > Chuck> To me, the genius (and unrecognized at the time) of the 6600 > Chuck> architecture was Cray's discarding the idea of a "condition > Chuck> code" in the IBM sense, wherein the state of a result is > Chuck> actually divorced from the result itself. > >That's useful indeed, though there were plenty of other machines back >then where this was true. I believe the more significant innovations >were the extensive parallelism and the quantity of registers. A lot of those ideas were result of experimental machines that preceeded them. TX2 came to mind as it had fast registers and core. Other ideas embodied were dual ALU, it could be used as 18bits or two 9bit alu. While the machine was a test bed to transistor logic it was also a system archetecture test bed as well. >Sure was. 600 timesharing terminals on a pair of 10 MHz processors is >pretty slick. (Come to think of it, over 9000 timesharing terminals >on a single Alpha-based descendant of that system is mighty >impressive, too.) > > paul I remember the BOCES LIRICS (LI NY) PDP-10 system in 1971 running around 500users at anyone time. Used to run a lot of idle cycles even them. Allison

18 years, 8 months

TRS-80 Mod 16

by Alwrcker82＠wmconnect.com

Something is missing my message was: > , I am getting a TRS-80 Mod 16 but no keyboard but I have a Mod II keyboard > and wonder if it will work till I find one fof the Mod 16. > Thanks for any help, Al DePermentier Alwrcker82 at wmconnect.com

18 years, 8 months

OT: Lowest-power small server solutions

by ajp166＠bellatlantic.net

> >Subject: Re: OT: Lowest-power small server solutions > Date: Tue, 01 Nov 2005 16:09:01 +0000 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > >Chuck Guzis wrote: >> This may be appropriate for another list, but it seems to me that there's >> plenty of applicable knowledge here. >> >> Right now, we're using an older Compaq Deskpro P3-600 box as our incoming >> Linux server. Basically, it connects with the DSL modem and contains IP >> masquerading, DNS caching, firewall and fetchmail/procmail/qmail tasks >> (SpamAssassin included). It runs 24x7 with no problem, as it has for the >> last 5 or 6 years. Built like a tank. I wonder if you even need a P200 for that. I used to manage a networks that had a 486dx/66 doing all but SpamaAssassin. For the rate it had to handle on the DSL port (actually fractional T1 256kb/S) it never seemed to be working hard. The PS in it was only 200W and nowhere was it ever stressed. It's claim to fame was running at room temp over a weekend in the summer with both PS and CPU fan siezed without melting or even getting upset. Also an older 500mb-1gb drive will use less power than a newer fast spinning drive. Or better yet netboot it and only keep a floppy. Pull all the IO you don't need and run the video at 640x480x256 as a further power reduction. Use a monitor (or KVM switch) as you don't need a monitor save to check on it. Allison

18 years, 8 months

FPGA VAX update

by dave04a＠dunfield.com

Scott, >I have a simple 8088-based SBC design wired up and waiting for motivation to >put together some test firmware. The main thing that has kept me from bringing >it up is the difficulty in getting x86-based machine language development tools >going. I'm used to little 4 and 8-bit assemblers where you can plop down a few >ORG statements and have it all resident in a ROM, and almost all the x86 asm >tools start from the assumption you are running on DOS and have no direct control >of the memory map. My ASM86 assembler is a "bare metal" assembler, it uses ORG, and outputs Intel (or Motorola) hex format download records (which can be converted by my HEXFMT into a pure binary file if that is your preference). It does not assume any OS, and does not require any special/weird setup sequences - just translates instructions into opcodes. ASM86 is a simple command line .EXE, runs under DOS up, does not require any installation or other such stuff - very easy to get going. I also have two 8086 debuggers that go with it: HDM86 is a "Hardware Debug Monitor" it gives you basic read/write/dump, but the nice thing about it is that it need NO memory - as long as you have the ROM and UART working, you can run it (even if you don't have the UART working, you can use it's polling to debug, so all you really need to get started is the ROM). Takes about 1.25k of ROM MON86 is a much more powerful monitor, which features all the goodies, memory and register dump/edit, breakpoints, single-step, disassembler, lots more... (It does need 160 bytes of RAM and about 3k of ROM). These tools should be all that you need to get your 8088 system up and running, and I'll be happy to send them to ya - contact me off-list if you would like them. I also have a decent disassembler for the 8086 instruction set which will let you define memory areas/types, build symbol tables for you etc. Also for "bare metal", but it doesn't sound like you will need this as you are writing "all new" code. In case you are also a 'C' programmer, I also have a 8086 "bare metal" version of my Micro-C compiler - much of what I said about the assembler applies to this (in fact, the C compiler produces assembly source which it them runs through the ASM86 assembler). FWIW, I have similar assemblers for a couple dozen other small processor architectures, as well as monitors, disassemblers and C compilers for many of them. Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html

18 years, 8 months

What are your favorite electronic/computer surplus stores in the Bay area

by GFisher＠tristonecapital.com

Thanks to all who replied to me, I going to have a busy Friday.! For the benefit of all my fellow lurkers, here is a website many mentioned as a great place to start looking for surplus electonics stores (and was in some earlier cctalk messages a few months back, shame on me!) http://www.bluefeathertech.com/technoid/calswapindex.html Gary Fisher This e-mail and any attachments may contain confidential and privileged information. If you are not the intended recipient, please notify the sender immediately by return e-mail, delete this e-mail and destroy any copies. Any dissemination or use of this information by a person other than the intended recipient is unauthorized and may be illegal. Unless otherwise stated, opinions expressed in this e-mail are those of the author and are not endorsed by the author's employer.

18 years, 8 months

Discharging a VT100 CRT

by ISC277＠CLCILLINOIS.EDU

Okay, I'm going to try and take another crack at replacing the flyback on my VT100. A few months ago I almost did, and chickened out. I'm very very afraid to do so, as the idea of trying to discharge the CRT scares me very much. The terminal has been off and disconnected from power for at least 2-3 months now. This is what I've learned so far from reading: Put one hand in your back pocket. Use an insulated screwdriver with alligator clips on either end, one to the screwdriver blade, one to the frame (VT100 service manual says the frame right above the CRT is where you should ground to). Place the screwdriver under the anode cap and touch the metal connection underneath. Wait till the crackling stops. Remove the anode cap. Can anyone reassure me that this is a semi-safe procedure? Has anyone done this sort of thing before? Thanks Julian

18 years, 8 months

FPGA VAX update

by ajp166＠bellatlantic.net

> >Subject: Re: FPGA VAX update > From: Holger Veit <holger.veit at ais.fraunhofer.de> > Date: Thu, 03 Nov 2005 14:08:04 +0100 > To: General Discussion: On-Topic Posts Only <cctech at classiccmp.org> > >woodelf wrote: > >> Bj?rn Vermo wrote: >> >>> >>> Apple comes to mind. You can pick up a G4 really cheap these days. >>> Whether you want to run BSD (OS X) or Linux is a matter of taste. >>> IBM have some PPc development systems (Walnut if I recall right) >>> which can run both Linux and QNX, but I have no idea how to get one >>> or what they sell for. >> >> >> I guess nobody even considers building a computer from scratch. :( >> >About thirty years ago, when I was pretty much younger :-), I built a >classical TTL computer (with 74181 ALUs etc.) almost from scratch, >basically from schematic fragments from the TTL databook and TTL >cookbook and some electronics magazines; well - if it were really from >scratch, then even so "highly integrated chips" like the 74181 were >prohibited as well. Looking back, this had almost all characteristics of >a real computer. > >There are two aspects IMHO why this does no longer happen today: >- what was a known magazine in the past, would today perhaps >realistically called "Un-Popular Electronics", the knowledge of >electronics from the ground up is dying out; and with the continuing >"digitalization" of technology, it is an ever increasing hurdle to get >started - the classical AM detector radio I built as a newbie will >nowadays no longer attract anyone - you can get a gadget which is better >by several magnitudes for a fraction of the expenses you'd have for >soldering your thing. >- The tools you have are too user friendly (!); i.e. you could rather >easily click something together, be it software or VHDL code for an FPGA >without ever needing to understand what is really going on. The "soul of >a new machine" guys that traced glitches with a logic analyzer in a >large wire-wrapped TTL graveyard are gone - such a machine had the >necessary wow factor. No surprise when a VAX in an FPGA - see subject - >is not really interesting. It is possible - that's it. But what does one >gain? It is like solving a 10000 pieces puzzle; spend time and don't >learn really much. >When Hillary climbed the Mount Everest 50 years ago, it was something >new, extraordinary. When tourist nowadays use sort of stairways to reach >the top (okay, it's not *that* extreme now), it is just uninteresting. >But standing on the top, is still a challenge and an experience for the >individual. However, what we lost now is a sense of wonder - that small >ALU based TTL circuit was built by myself, and I did it, and it is >irrelevant that some idiot could download a digital simulator and click >the same circuit together on a PC screen. I guess this is what makes the >difference between a real PDP-11 with some ridiculous 5MB storage disks >compared to a SIMH emulator running on a 3GHz Pentium. >Watch the blinkenlights. > >Holger Ah, for the adventure of it all. Well put. Another extreme is those that seem to be interested in building usable minimalist machines with TTL using the fewest packages. Allison

18 years, 8 months

← Newer
1
...
60
61
62
63
64
65
66
...
70
Older →

Jump to page:

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 November 2005