Ersatz-11 V7.3 is finished. CDs have been mailed to users with current
update subscriptions, and the free Demo version may be downloaded from
www.dbit.com/demo.html as usual.
E11 V7.3 has the following new features:
- My favorite one: a BREAKPOINT command which accepts arbitrary boolean
test expressions, compiles them into native x86 code (to reduce the speed
penalty), and incorporates them (until disabled with BREAK/CLEAR) into
the main fetch/decode loop). Examples:
break pc >= 2000 and pc < 3000 and @(r4+4) = 42776
(range of code with specified value in block pointed to by R4)
break ci(pc)&177400 = 104000
(about to fetch an EMT instruction)
break phys(14634520) <> 3044
(location at physical address gets changed from expected value)
Errors at run-time are silent. If a specified test causes a bus timeout,
odd address trap, or division by 0, the test fails. Well OK division by
*constant* 0 gives an error but I just mean nothing damaging happens if
the registers aren't pointing where you thought, etc.
- A few rare antique emulated devices: DC11 SLU. Basically similar to
the DL11 (ignoring the extra CSR bits and programming it like a DL11A
works), but it also has a settable baud rate and modem control which
is different from how it was done on DL11s.
- Also the DM11 single-speed serial mux (not that E11 minds running each
line at a different speed, but the original did). It uses DMA for
transmission but also for reception into an in-core FIFO which the
documentation adorably calls the "tumble table". And yes this is the
origin of the DM11BB modem-control option more commonly used on the DH11.
There's a new command to tell DM11BBs which to attach to (the default is
still the DH11 with the same controller letter).
- Finally, the justifiably forgotten TR79F 1600 BPI tape controller for
TR79 drives (really HP7970Es), which includes the parity track in core
with each byte of tape data taking up a word, so it's a pain to program.
But it had 1600 BPI pretty early. The only driver I can find for the
TR79F is in the "TRDP" version of XXDP, which is on Bitsavers as a scan
of a microfiche of the listing. It can be used to load the ZTRAB0
diagnostic (the only other program I know of for the TR79F), but of
course the test immediately trashes your boot tape. I felt dumb.
- Driver for raw ATA/SATA/ATAPI disks (DOS and stand-alone versions).
- Driver for National Instruments PCI-DIO-96 digital I/O card (DOS and
stand-alone versions). It's a bad fit to emulating the DRV11/DR11C
(ASSIGN OA: DIO96: does work but you'd have to wire up an adapter with
buffering since the drivers are rated at only 2.5 mA) but it's probably
the most common digital I/O board around. Even though it's PCI (not PCIe),
it's still made new (at great expense), but cheap used examples are
- Ability to use a digital I/O card to drive real display and switch
registers. Wiring up a blinky-lights board for your $25 eBay PCI-DIO-96
is a lot easier than making one for current PC busses, even if the
100-pin D-shell plug is a pain (but AMP makes an IDC connector that
brings it out to two 50-pin Bergs)..
- SET HISTOGRAM command enables/disables histogram of PDP-11 opcode usage
(which again is temporarily compiled into the main loop when enabled).
HISTOGRAM command displays the results or saves them to a file.
- EXAMINE/DEPOSIT /BYTE /WORD /LONG /QUAD switches support various data
types besides just words. Finally.
- MOUNT <tape> FILE.TAP /LENGTH:n or /SIZELIMIT:nMB enables emulation of
EOT early warning flag (giving the approximate maximum length of the
tape in feet or megabytes). Not generally needed (who minds an unlimited
tape?), but some diags want to fill a tape with test data all the way
- ASSIGN <TTY or digital I/O device> NULL: /LOOPBACK switch. Does what
- Experimental POWERFAIL command simulates power failures on command,
or SET POWERFAIL command schedules one at shutdown (with a core dump
to a file). Thank you Oleg Safiullin for the idea! Might need some
changes -- I've never dealt with power failures on a real PDP-11.
- Dramatically improved timer precision in DOS and stand-alone versions.
SET THROTTLE in particular is silky smooth, but this improvement affects
many many things.
- All commands that take a time duration as a parameter will now accept a
decimal point and/or unit suffix. The default units are the same as in
previous versions. So instead of SET THROTTLE DELAY=1 (microseconds),
you can use SET THROTTLE DELAY=1.2 or SET THROTTLE DELAY=1200NS (values
will be rounded if needed). I hadn't realized so many places use time
values -- I might have missed something.
There are also many bug fixes and minor changes, but most importantly:
- WMSG.LOG file that grows and grows (in Windows versions). Sorry about
that! That was supposed to be disabled in the released version. Well
it is now.
I don't know if anyone here has the interest or capability to do it, but
creating a replica of the blue tape trays with the clear overlay that
one could sell for a few bucks with some random fanfold copies of DEC or
other diagnostics would be nice.
Perhaps if there were a ready source of replicas with a perpetual
listing or 10 to overwhelm the auctions with 100 and 300 dollar auctions
for the genuine originals the originals would be listed and sold for a
I'm sure there there are things going to people with no idea what they
have which would have been nice to image and save. I would think
someone with vacuum molding and some skill with plastics could do the
trays. not sure about the source of tapes to sell with them, maybe that
does justify some extra expense.
People with working readers and libraries of tapes might like them as well.
Would someone with a real DEC VT terminal be so kind and help settle, once and for all, the question about how they behave with respect to line-wrapping, exactly? It is something that isn't covered by any standard, nor by any of DEC's manuals, and there is a scarcity of information online that is not vague repetition of folklore.
There are emulators, of course, but these do not agree with one another to the point that they can be trusted, and are probably just copying each other in any case. It seems that some ground truth would be welcome, for the benefit of both application and emulator writers.
First, the problem: A VT100, when in "auto-wrap" mode, will wrap text from one line to the next in a peculiar way, sometimes called "soft-wrap" or "the VT100 glitch". When the terminal receives a printable character with the cursor in the last column, the character is put at that location but the cursor remains in place. Instead, the terminal enters a pending wrap state, which causes the cursor to wrap before next printable character is displayed. This behaviour is widely known.
What isn't widely known are the finer points:
* What control codes will cancel the wrap state?
* What cursor position is reported in the wrap state?
* Do any operations behave differently in the wrap state?
* Is the wrap state saved/restored by the save/restore cursor codes?
and so on. Every emulator programmer seems to have a different answer to these questions.
If you have a VT100, VT220 or later model (compatibles like Wyse are also of interest) and have a spare moment, I'd be most grateful if you would download and run
in that terminal, and send me the resulting output. (Redirect stdout to save the report.)
The test program is not comprehensive but would give us a good idea of the rules.
Current results, right now only from various emulators, are found in
OK, it's official. I rarely criticize mail interfaces, because they're usually
mostly innocuous. However, today's change makes life a lot more difficult.
In the past, it was simple to direct a reply to an individual instead of to the
list because the originator's address was right there in the From: header. As
of today, the list address is substituted for that, so that it is impossible to
respond privately unless you happen to have a bunch of old messages archived and
the person to whom you want to respond is someone who has written previously.
Is this a conscious choice, or a configurable with a different default setting
in a new mail system than was previously in place? However it came to be, it
greatly diminishes communications quality (IMAO).
Vintage Computing Sr. Systems Engineer
Living Computers: Museum + Labs
2245 1st Avenue S
Seattle, WA 98134
mailto:RichA at LivingComputers.orghttp://www.LivingComputers.org/
This is probably a long shot, but does anyone have a Sparcbook 3TX hard
drive? I know they're difficult to find.
I have a 3TX in great condition, but no drive.
(hopefully this isn't a repost, I tried this when the list was having
issues and don't think it went through)
ben at bensinclair.com