[cctalk] Re: programming the IBM PC synchronous serial boards (Northstar Advantage project)
On Fri, Dec 22, 2023 at 10:20 PM Chuck Guzis via cctalk wrote: > Sync (Bisync, SDLC/HDLC) was fairly popular back in the day for linking > with mainframes. (Think, for example, IBM HASP). On PCs and the like, > the Intel 8251 was used a lot, but even the Signetics 2651 has the sync > mode, with the ability to recognize a double-byte sync. The COMBOARD line of Bisync and SNA protocol engines came out of the HASPBOX product, which was 100% DEC hardware, so we started with a COM5025 (same as at least one of DEC's sync seral boards) and we later moved to the Zilog Z8530 (but only ever used its second port as a local async debug port) > The protocol for any of the above higher-level protocols is fairly > complex and there are manuals for that Yeah, implementing Bisync from scratch on a new platform would be quite an effort. There are a few poorly-documented "gotchas" to work through/around. -ethan
[cctalk] Re: programming the IBM PC synchronous serial boards (Northstar Advantage project)
On 12/22/23 16:02, Glen Slick via cctalk wrote: > On Fri, Dec 22, 2023 at 2:13 PM r.stricklin via cctalk > wrote: >> >> Did IBM ever publish programming information for their PC SDLC or BiSync >> communications boards? I’m wondering about the possibility of programming >> one to drive the synchronous protocol needed for “booting” a Northstar >> Advantage over its serial port. >> > > Are you looking for something beyond the low level information in the > IBM Options and Adapters reference manuals? > > https://minuszerodegrees.net/oa/oa.htm > > IBM Synchronous Data Link Control (SDLC) Adapter > https://minuszerodegrees.net/oa/OA%20-%20IBM%20SDLC%20Adapter.pdf > > IBM Binary Synchronous Communications (BSC) Adapter > https://minuszerodegrees.net/oa/OA%20-%20IBM%20Binary%20Synchronous%20Communications%20Adapter.pdf Sync (Bisync, SDLC/HDLC) was fairly popular back in the day for linking with mainframes. (Think, for example, IBM HASP). On PCs and the like, the Intel 8251 was used a lot, but even the Signetics 2651 has the sync mode, with the ability to recognize a double-byte sync. One key difference from async mode is that while async operates with start and stop bits to synchronize character data, sync sends as a block of data with no start/stop overhead. Idle times are automatically filled with SYN characters. The protocol for any of the above higher-level protocols is fairly complex and there are manuals for that. As far as software, I may have some for 8085/8251 kicking around. Interestingly, I've used synchronous mode to read certain proprietary floppy formats. After all, the two are cousins. You have Idle characters, ID fields, etc. Sync mode can be pretty efficient on a leased line. It was pretty much the default back in the Bell 408 days. --Chuck
[cctalk] Re: programming the IBM PC synchronous serial boards (Northstar Advantage project)
> On Dec 22, 2023, at 4:02 PM, Glen Slick via cctalk > wrote: > > On Fri, Dec 22, 2023 at 2:13 PM r.stricklin via cctalk > wrote: >> >> Did IBM ever publish programming information for their PC SDLC or BiSync >> communications boards? I’m wondering about the possibility of programming >> one to drive the synchronous protocol needed for “booting” a Northstar >> Advantage over its serial port. >> > > Are you looking for something beyond the low level information in the > IBM Options and Adapters reference manuals? > No, I guess not. I don’t know why I assumed they wouldn’t be in there. ok bear.
[cctalk] some old PC-DOS file managers
Hey all! I'm looking for a couple "file manager" type pieces of software. I can't find them on WinWorld. First one is from about 1984-1985, possibly called DRBOSS.COM, I just remember it used IBM extended graphics for "window" borders (which were colored red) and the filenames were either in gray or green. The main feature was you could select a few files at a time, then do some operation on those selected ones. And as a .COM it was well under 64K. The other is from around 1996, and called MWIZ or Menu Wizard. Apparently there were a few variations with possibly the same/similar name. All I recall about this one is it came with both a .EXE and a .COM, and was written by a person named Tony. I believe it was available on the '96 or '97 BYTE magazine CD, and possibly also on CompuServe (I'm not current on what the state of any CompuServe archives are these days). Not urgent - just curious if they could be found. And if anyone is in an MS-DOS mood throughout the holiday break: I still find my ancient CDIR.EXE useful even in DOSBOX or on my physical IBM 5150. It is available in my utility collection archived here: https://github.com/voidstar78/VUC4DOS For other early IBM PC notes (like floppy drive emulators and NIC setup), I have some notes here: https://voidstar.blog/ibm-pc-5150-notes/ (including all about using the tape deck!) -Steve / v*
[cctalk] Re: programming the IBM PC synchronous serial boards (Northstar Advantage project)
On Fri, Dec 22, 2023 at 2:13 PM r.stricklin via cctalk wrote: > > Did IBM ever publish programming information for their PC SDLC or BiSync > communications boards? I’m wondering about the possibility of programming one > to drive the synchronous protocol needed for “booting” a Northstar Advantage > over its serial port. > Are you looking for something beyond the low level information in the IBM Options and Adapters reference manuals? https://minuszerodegrees.net/oa/oa.htm IBM Synchronous Data Link Control (SDLC) Adapter https://minuszerodegrees.net/oa/OA%20-%20IBM%20SDLC%20Adapter.pdf IBM Binary Synchronous Communications (BSC) Adapter https://minuszerodegrees.net/oa/OA%20-%20IBM%20Binary%20Synchronous%20Communications%20Adapter.pdf
[cctalk] VT100: Replacement for B411 Transistor
I think I have got my VT100 basically working now except for the actual video display. I think there is a problem with the transistor that drives the flyback transformer. This is Q414 on page 58 of the Feb82 schematic on BitSavers (https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Schematic_Feb82. pdf). I have removed it from the circuit and tested it with the diode tester of my multimeter. It does not test as two diodes, indeed across Collector-Base the multimeter beeps for a short circuit, and so I am fairly sure it is bad, The part is the one with the heatsink as shown in this picture: https://rjarratt.files.wordpress.com/2023/12/img_20231221_112305.jpg. I have found some information on it here: https://www.web-bcs.com/transistor/tc/b0/B411.php but the Feb82 schematic shows it is a BU407D. My video board is not exactly the same as the one in the schematic despite having the same DEC part number, but the circuit that drives the flyback is the same on the secondary side of T403, and includes the optional diode CR406 in the form of another B411 transistor that is not connected at the emitter. I am trying to identify a replacement and could do with some help identifying one. I can't find a full datasheet for the B411, all I can find is this https://www.web-bcs.com/transistor/tc/b0/B411.php, which seems to match the part I need to replace, and I have also found one for a BU407 (not BU407D) here https://www.mouser.co.uk/datasheet/2/308/1/BU407_D-2310257.pdf. I have tried to find something that meets or exceeds the voltage, current and switching time specs. I have found a couple of possible replacements and would welcome opinions on their suitability: https://www.farnell.com/datasheets/2861437.pdf and https://www.farnell.com/datasheets/3033460.pdf (assuming that the switching times are a typo and they are in microseconds rather than seconds) Do these seem like suitable replacements? Thanks Rob
[cctalk] programming the IBM PC synchronous serial boards (Northstar Advantage project)
Did IBM ever publish programming information for their PC SDLC or BiSync communications boards? I’m wondering about the possibility of programming one to drive the synchronous protocol needed for “booting” a Northstar Advantage over its serial port. Or, for that matter, wondering what Northstar had in mind when they made that protocol synchronous - what would they have had driving it? ok bear.
