DEC backplane power connectors
Are the power connectors on the DEC PDP-11 backplanes (e.g. DD11-DF 15pin and 6pin) Molex or other? Are they still commonly available? --tnx --tom
Re: Want To Buy: HP 9817 Monitor and Keyboard
On 2021-01-26 6:44 p.m., TangentDelta via cctalk wrote: I have an HP 9817 and 9133D disk drive that I am trying to get going. The 9817 has a 98204B composite video card. I can mess with the settings of a composite monitor enough to barely read the text on the screen, which indicates that the machine is trying to boot from device A. I tried to make an image of the hard drive in the 9133D using Dave's MFM emulator, but the drive is pretty much toast and I wasn't able to recover much from it. If I connect the drive to the computer, it fails to boot and goes into BASIC. I do not have a compatible HP monitor or HIL keyboard to use with the machine. I was planning on building a PS2 to HIL converter, but having an actual keyboard would be far easier. Likewise, having a monitor would be easier than abusing a normal composite display into working. It looks like there were a bunch of compatible monitors back in the day. The 35721 and 35731B are mentioned on the HP Museum website. I have a 35731A that is the 110V North American version that I could part with for a reasonable offer, however it is quite large and shipping outside of North America would probably be very expensive, not to mention the 110V 60Hz power requirement. Paul.
Want To Buy: HP 9817 Monitor and Keyboard
I have an HP 9817 and 9133D disk drive that I am trying to get going. The 9817 has a 98204B composite video card. I can mess with the settings of a composite monitor enough to barely read the text on the screen, which indicates that the machine is trying to boot from device A. I tried to make an image of the hard drive in the 9133D using Dave's MFM emulator, but the drive is pretty much toast and I wasn't able to recover much from it. If I connect the drive to the computer, it fails to boot and goes into BASIC. I do not have a compatible HP monitor or HIL keyboard to use with the machine. I was planning on building a PS2 to HIL converter, but having an actual keyboard would be far easier. Likewise, having a monitor would be easier than abusing a normal composite display into working. It looks like there were a bunch of compatible monitors back in the day. The 35721 and 35731B are mentioned on the HP Museum website.
Re: DDCMP sync?
> On Jan 26, 2021, at 2:35 PM, Mattis Lind wrote: > > > Hello Paul, > > ... > >> The framing is different but no harder, I think. And I was thinking of >> leaving the protocol state machine to the host, so the microcontroller would >> only do framing -- deliver completed good frames to the host without >> interpretation. >> > I made a very quick check on DDCMP. It looks a bit like BSC but using a byte > counter rather than various characters to end the frame. That would probably > simplify the software. It seems to use SYN SYN which is identical to BSC so > that part of the code that takes care of framing could probably be used > directly. Yes, though the sync byte has a different value, the fact that it's called SYN is a bit misleading if you're used to the SYN used in BISYNC. > There are also the small STM32F411 Weact boards out there > (https://github.com/WeActTC/MiniF4-STM32F4x1). 100 MHz and the ART > accelerator. From other projects where I have used the STM32F103 have seen > that it executes slower than I expected since it was reading code from flash. > The ART accelerator should help here to achieve near zero wait state so > perhaps 1 Mbit/s would be possible? What is an ART? I looked a bit at that Weact thing but got lost in the fulminating about "pirated" copies. Seriously? Open source designs are meant to be copied; "pirated" is a nonsensical term. Low quality copies, that would be a valid complaint. (The use of leaded solder, all things equal, increases quality rather than reducing it, by the way.) The ARM chips used in the Adafruit boards I've used have on-chip flash so I'd assume that runs quickly, but I'll have to try to find out. > ... > If you have further questions feel free to ask. Would be nice to add DDCMP > support as well! Then perhaps I could try those M8203 / M8207 boards I have > sitting here. Thanks, will keep that in mind. What sort of connection and signaling do your DMR boards use? paul
Re: DDCMP sync?
Hello Paul, > > Mattis, thanks! That's an implementation along the lines I was thinking. > If yours can get close to 1 Mb/s, chances are one could get all the way > there with the Arduino Itsy Bitsy M4, that's a 120 MHz ARM chip (Cortex > M4). It has USB built-in. I'll study your code; that approach of using a > fast loop for consistent reliable timing matches what I was thinking. > > Actually the STM32F103 has built-in USB so there is no difference there, really. > DDCMP is a bit harder because it's normally full duplex. I think the code should handle full-duplex, but I have not really tested it. At least Tx and Rx is separate flows in the software. > The framing is different but no harder, I think. And I was thinking of > leaving the protocol state machine to the host, so the microcontroller > would only do framing -- deliver completed good frames to the host without > interpretation. > I made a very quick check on DDCMP. It looks a bit like BSC but using a byte counter rather than various characters to end the frame. That would probably simplify the software. It seems to use SYN SYN which is identical to BSC so that part of the code that takes care of framing could probably be used directly. There are also the small STM32F411 Weact boards out there ( https://github.com/WeActTC/MiniF4-STM32F4x1). 100 MHz and the ART accelerator. From other projects where I have used the STM32F103 have seen that it executes slower than I expected since it was reading code from flash. The ART accelerator should help here to achieve near zero wait state so perhaps 1 Mbit/s would be possible? I made the design of the board so that it should work with the Weact board as well. But never got around testing it, mainly because the stm32duino hasn't support for them. But converting to the more official STM32 Arduino core would probably not be that hard. If you have further questions feel free to ask. Would be nice to add DDCMP support as well! Then perhaps I could try those M8203 / M8207 boards I have sitting here. /Mattis > > paul > > >
Re: DDCMP sync?
> On Jan 26, 2021, at 1:24 PM, Peter Coghlan via cctalk > wrote: > > I wrote: >> >>> >>> The other option would be synchronous links, which would enable connections >>> to DMC11 or the like at speeds up to 1 Mb/s. But synchronous comm devices >>> that connect to modern computers aren't so easy to find, though I have seen >>> a few. >>> >> >> Not what would be called modern these days but I managed to run across two >> MicroVAX 3100 machines with DST32/DHT32 synchronous serial interfaces in them >> plus two V.24 and one each of V.35 and X.21 cables that will plug into them. >> With some help from the people here, I managed to get the machines talking to >> each other using a null modem between the two V.24 cables. I also have two >> nearly identical syncronous modems, one with a V.35 interface and another >> with >> an X.21 interface but I have not managed to get these to talk to each other, >> probably because they can't be configured to match any of the speeds the >> DST32/DHT32 interfaces can do. >> > > Forget I said anything. the DST32/DHT32 won't do anything like 1 Mb/s. > Why do you want to go so fast? 1 Mb/s is the top speed of the DMC with the coax local "integral modem" connection. I don't know if the real modem card could go that fast. Probably not; the top speed requires special microcode. But the DMR, with a faster engine, can do 1 Mb/s without trouble. I suspect that if you take the modem flavor of the DMR and manage to clock those signals at 1 MHz you can indeed send that fast. Of course, RS232 officially isn't rated anywhere near that high (9600 I think is the official limit). Other physical links like V.35 or RS422 were used at the time to go faster. In every case, you can usually get away with going well over the limit if the cables are short enough, and especially if the cables are better quality than the minimum. For example, the DMC/DMR local connection is specified to use triax, but it wouldn't surprise me at all if Cat 5 Ethernet twisted pair cable works just as well. The main question for new work is what people have out there to connect to. The only thing I have is a Pro. That has a comm port with a USART, which will do sync just fine but tops out at 9600 bps or so due to having a tiny FIFO. That's RS232. I have no DMC or DMR or anything else fast in my collection. Thanks for the pointer to the Z85C30. Nice chip but it costs more than an Arduino (!); I was thinking of a software-only solution if possible. Mattis, thanks! That's an implementation along the lines I was thinking. If yours can get close to 1 Mb/s, chances are one could get all the way there with the Arduino Itsy Bitsy M4, that's a 120 MHz ARM chip (Cortex M4). It has USB built-in. I'll study your code; that approach of using a fast loop for consistent reliable timing matches what I was thinking. DDCMP is a bit harder because it's normally full duplex. The framing is different but no harder, I think. And I was thinking of leaving the protocol state machine to the host, so the microcontroller would only do framing -- deliver completed good frames to the host without interpretation. paul
Looking for HP marketing posters, in English and other world laguages large systems like HP-3000 as well as HP-150 and other pc and workstations... urgent need for monarch butterfly HP-150 poster!!!
Looking for HP marketing posters, in English and other world laguages large systems like HP-3000 as well as HP-150 and other pc and workstations... urgent need for monarch butterfly HP-150 poster!!! Will be part of smecc museum hp display. - Thanks Ed#
Re: DDCMP sync?
I wrote: > >> >> The other option would be synchronous links, which would enable connections >> to DMC11 or the like at speeds up to 1 Mb/s. But synchronous comm devices >> that connect to modern computers aren't so easy to find, though I have seen >> a few. >> > > Not what would be called modern these days but I managed to run across two > MicroVAX 3100 machines with DST32/DHT32 synchronous serial interfaces in them > plus two V.24 and one each of V.35 and X.21 cables that will plug into them. > With some help from the people here, I managed to get the machines talking to > each other using a null modem between the two V.24 cables. I also have two > nearly identical syncronous modems, one with a V.35 interface and another with > an X.21 interface but I have not managed to get these to talk to each other, > probably because they can't be configured to match any of the speeds the > DST32/DHT32 interfaces can do. > Forget I said anything. the DST32/DHT32 won't do anything like 1 Mb/s. Why do you want to go so fast? Regards, Peter Coghlan.
Re: DDCMP sync?
> > The other option would be synchronous links, which would enable connections > to DMC11 or the like at speeds up to 1 Mb/s. But synchronous comm devices > that connect to modern computers aren't so easy to find, though I have seen > a few. > Not what would be called modern these days but I managed to run across two MicroVAX 3100 machines with DST32/DHT32 synchronous serial interfaces in them plus two V.24 and one each of V.35 and X.21 cables that will plug into them. With some help from the people here, I managed to get the machines talking to each other using a null modem between the two V.24 cables. I also have two nearly identical syncronous modems, one with a V.35 interface and another with an X.21 interface but I have not managed to get these to talk to each other, probably because they can't be configured to match any of the speeds the DST32/DHT32 interfaces can do. One of the MicroVAXes has since died (again) and I haven't got around to looking at it yet to see what is wrong this time. Regards, Peter Coghlan.
