test-drb January 2014

test-drb@ccmp.vtda.org

224 participants
263 discussions

by aek＠bitsavers.org

Here is a first draft. Anything wrong/missing architecturally? Ethernet Bus Interface Board 2013-12-21 aek +--------------+ | 4Mx16 BBSRAM | +------+ | AS6C1616 | | | +------+-------+ LEDs - + ARM | | SD -- + uCtl | JTAG +------+-------+ USB -- + +-----------+ | -> Simulated Peripheral Registers ENET - + +-----------+ FPGA | Bus Monitor / Adr Mapper SER?-- | | ARM intf | | Bus Master Controler +------+ +------+-------+ | +------+-------+ | | | 5v<->3.3v | | Bus Buffers | +--------------+ The entire address space of the host is maintained in the SRAM ARM performs DMA by placing the data to be transfered where it will appear on the host. If the local memory is the system memory, we're done, just clean up the DMA registers. If not the FPGA does DMA to synchronize local memory with core. 3 cycle data break side effects will have to be investigated. Does any driver watch the value of ADR,WC in memory while a DMA is occurring? Bus transactions are snooped to maintain consistency on the PDP-8 where some core memory is on the Omnibus. This may work OK on small 11's, too but won't be the right thing to do on an 11/70 where memory transactions occur that are invisible to the Unibus. It should be possible to simulate all the front panel functions of an Omnibus machine and to capture all of the state in real time for all of the major registers from watching Omnibus transactions. It is also possible to adapt the board to be a dedicated bus analyzer or soft front panel or peripheral/ memory exerciser for any supported bus architecture. All registers and supported peripherals are obviously soft. The configuration is stored on the SD, along with the FPGA bitstream. Everything should be reconfigurable through transactions across the Ethernet by updating files on the SD card. Battery-backed SRAM was chosen over FRAM because of cost. I'm not sure if a local serial interface would be that useful other than for debugging messages. There are a small number of LEDs hung off of a STP08DP05 Small local SPI NOVRAM for configuration/bitstream storage? SD hot-swap? Larger local storage? Is performance an issue on Omnibus/Qbus/Unibus CPUs? They are slow enough busses that they'll saturate in the couple MB/sec range. Write-through track caching in SRAM? Block mode on QBus .. and on and on Ethernet Peripheral Controller This is the mirror of the Bus Interface Board. It provides block-level data that the Bus Interface sends into the computer. In its simplest form, there is no hardware at all, it is just a simulation running on a computer on the network. The second simplest is hardware that understands the Ethernet peripheral command protocol but has a simple enough interface to the physical device that no FPGA is required. It may also not need any local storage. The most complicated could look like the Bus Interface Board, with local SRAM and FPGA. A Diskferret-like forensic disk interface would be an example of this.

10 years, 6 months

Need DEC BC80J-20 cable

by charlesmorris800＠centurytel.net

I'm looking for a BC80J-20 cable... that's the one that goes from the RL controller card to the first drive, with a 40 pin header on one end and that big quick-release connector on the other end. (I am tired of failures and damage to the rigged ribbon cable/IDC header I've been using, and now that I'm chasing a fault in my two- RL02 system, I can't swap drives without taking the cover off to get to the header connectors inside). thanks Charles

10 years, 6 months

Lot of fiche and books on UK ebay

by pontus＠update.uu.se

I thought this might interest some of you. I'd go for it myself but the bulk of the books I don't want will raise the shipping costs to much. /P

10 years, 6 months

BNC video cables

by sales＠elecplus.com

Ask and you shall receive.. 4 BNC to PC VGA, new, qty 4, approx 4 feet long, $15 each 3 BNC to PC VGA, used, qty 1, approx 3 feet long, $10 5 BNC to PC VGA, used, qty 1, approx 5 feet long, $15 4 BNC to 15-pin Rasterops PN 9000-0059, new but dusty, $15 (will not work on PC, wrong end) 4 BNC to 15-pin Rasterops PN 9000-0001, new, $15 (will not work on PC, wrong end) Shipping $6 for the 1st cable, and $3 each additional cable ground in US. Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 (830)792-3400 phone (830)792-3404 fax AOL IM elcpls _____ No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3658/6978 - Release Date: 01/05/14

10 years, 6 months

MFM Control Signals and RD disk size

by robert.jarratt＠ntlworld.com

As I don't have a logic analyser to help me with my analysis of the MFM interface, can anyone tell me how the MicroVAX 2000 determines disk size? I know it is related to the number of heads, but what does the drive do when the host asks for a head that does not exist? How does it report this back? The only thing I can think of is the Ready signal, could that be it? Regards Rob

10 years, 6 months

cctalk Digest, Vol 125, Issue 14

by seefriek＠gmail.com

From: Liam Proven <lproven at gmail.com> > So, an ad-hominem attack is your idea of a balanced reply, is it? Can't attack the message, attack the messenger. Good to see my assessment was spot on. KJ

10 years, 6 months

Ten classic electronic calculators from the 1970s and 1980s • The Register

by woyciesjes＠sbcglobal.net

For you calculator geeks out there.... http://www.theregister.co.uk/2014/01/03/ten_classic_calcutors/ -- --- Dave Woyciesjes --- ICQ# 905818 --- CompTIA A+ Certified IT Tech - http://certification.comptia.org/ --- HDI Certified Support Center Analyst - http://www.ThinkHDI.com/ Registered Linux user number 464583 "Computers have lots of memory but no imagination." "The problem with troubleshooting is that trouble shoots back." - from some guy on the internet.

10 years, 6 months

Possibly dumbest ebay ad ever...

by evan＠snarc.net

Someone put an Apple sticker on a briefcase. Asking price: $6,000. http://tinyurl.com/n8aw6gl

10 years, 6 months

Wanting a SWTPC 6800 but need more information

by billdeg＠buzz1.com

> I'm just wondering if anyone knows what a typical value for a single unit > with nothing fancy is? I note a recent auction had two of them together for > $1400 - Am I correct to imply from that that the value of an individual unit > is probably less than $700 (that set was unique due to the systems being > linked and that control box they had, I think). A working, complete, 1975-6 SWTPc with top and bezel, original backplane, original CPU and RAM with an MP-S card is worth $1000+. That would be the bare minimum system. $700 is too low for a working system. The newer 6809 SWTPc's would be worth less, maybe you can get one of these for $700. Bill

10 years, 6 months

3rd Party 11/730 memory boards

by seefriek＠gmail.com

I've seen a couple of vague references to 3rd party memory cards for the VAX 11/730, equivalent to the M8750, that used denser DRAM chips in order to use less power. Unfortunately, my google-fu has turned up nothing. Does anyone know who made these cards and what part number they would be (assuming they exist at all)? KJ

10 years, 6 months

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test-drb January 2014