Here's a PDP11 SIMH bug as old as the simulator itself: the reset_cpu routine sets the PS to 340 (interrupts disabled). This causes some versions of Lunar Lander not to work. In fact, the initial state of the PS is not architecturally standardized:
04: cleared (from schematics)
05: cleared (from manual)
20: cleared (from schematics)
34: cleared (from schematics), set to 340 on boot?
40: cleared (from schematics)
44: cleared on init, set to 340 on boot (from schematics, manual)
45: cleared (from schematics)
60: cleared (from schematics)
70: cleared (from schematics)
T11: set to 340 (from spec)
LSI11, F11: 4 mode behavior (from memory on power recovery, cleared on GO, 340 on boot, mode 3 undefined)
J11: 4 mode behavior (from memory on power recovery, cleared on GO, 340 on boot, 340 on jump to custom PROM)
The story seems to be this. All non-VLSI PDP11s used TTL chips to implement the PS, either discrete flip-flops, or 4b registers, or both.
Starting with the first system, the 11/20, they were wired clear on the processor INIT signal (power-up or front panel START switch), so that all internal state started as 0. This worked fine, because START also reset the Unibus and cleared all interrupt enables. So even though the processor was as IPL = 0, no interrupts were possible. Then along came the LSI11...
The LSI11 implemented a line-time clock with NO INTERRUPT DISABLE. Thus, if IPL was left at 0 and a bootstrap routine from a slow device was started (e.g., a floppy drive), the clock would tick, and an interrupt would occur, before the bootstrap routine finished. Because no vectors were set up, the processor would crash. So the LSI11 started the practice, carried over to all later PDP11 VLSI chips, of setting the PS to 340 before jumping to a boot ROM.
The T11 did this in all modes of startup, because its only startup behavior was to jump to a "boot" routine. It did not have a console of any kind.
Accordingly, it appears that the cpu_reset routine needs to set the PS based on the processor model. Further, all boot routines need to set the PS to 0 or 340 based on the processor model. (It's probably safe for boot routines just to set the PS to 340, but it's not technically
accurate.)
Show IOSPACE doesn't always get the number of devices right due to device creativity.
o The distinction between UNIT and DEVICE has blurred
o MUX devices merge several physical devices into one device/unit
o Dynamic device sizing has made things more volatile.
This edit solves the problem for SHOW IOSPACE by adding an (optional) word to the DIBs.
The word contains the amount of IO space consumed by each instance of the physical device that's being emulated.
E.G., if it's a DZ11, the device is the DZ11 module, or 8 lines, even though the MUX device may support 32.
This enables SHOW IOSPACE to determine the number of physical devices being emulated, which is what folks need when configuring software. The word may have other uses - in a generic dynamic device sizing routine - which is why the amount of IOSPACE per device was chosen rather than the 'number of physical devices.'
The edit should not make any existing device regress. If the new word (ulnt) is zero (not initialized), SHOW IOSPACE will default to the number of units in the device, or if there's no device (CPUs), 1 as before. If it is present, the number of devices is the calculated as total allocation/allocation-per-device.
The edit updates all the devices that seem to require this treatment, and all the processors that define the UNIBUS/QBUS DIBs.
Fixed auto configure bugs which didn't allow Fixed CSR Addresses or Fixed Vectors to be set using the auto configure information.
Fixed display of address and vectors to indicate that the assigned address and/or vector is in the floating set.
Added extended definitions to the auto configure table to reflect all known potential static and floating and static addresses as of VMS V5.5-2
Changed the name of the VAX 11/780 console floppy device name to RXC from RX (which collides with a Unibus name for the RX11).
- Removed flawed logic which assumed that sim_interval was meaningful when referenced by an asynchronous thread.
- Adjust the event_time of events removed from the asynch queue to account for the average time spent on the queue before the event was noticed by the instruction execution thread.
- Added a sim_activate_notbefore function which specifies an rtime which is the earliest time the event should fire.
- Changed the 'wakeup from idle' logic to force an immediate asynch queue check if the wakeup was not due to a timeout (i.e. it was due to an asynch queue insertion).
- Fixed the descrip.mms to build asynchronous support on AXP and IA64 VMS with kernel threads enabled
I’ve always wanted to have the option to have simulated devices behave
more naturally with respect to I/O operations. By more naturally I
mean that the current simulator model I/O is either polled (for asynchronous
things link Muxes and Network), or it is performed in the middle of some
instruction execution taking possibly many milliseconds (disk and/or tapes).
The existing model creates quite deterministic behavior which helps to debug
and understand issues, but it trades off potential instruction execution
while performing these I/O operations in between instruction execution.
To address this concept (while still retaining the potential advantages of
the original model), I’ve designed an Asynch I/O model extension for simh.
In order to flesh-out and debug this design, I’ve also refactored several
devices to utilize this capability. Please read the attached
0readmeAsynchIO.txt file for concept details about the approach.
In order to make disk devices easy to implement (within or without the
AsynchIO framework), I’ve created a sim_disk.c library which is modeled
on the sim_tape.c library to generalize disk I/O like tape I/O is
generalized in sim_tape.c. This sim_disk.c library now provides that
natural place to implement support for various disk implementation formats
(just like sim_tape support several formats, and one day will be the place
to add direct physical tape access). The current sim_disk library provides
the framework for direct support of 3 different disk formats:
1) standard simh disk format
2) platform specific physical disk access
and 3) platform independent Virtual Disk format.
The Virtual Disk format is an implementation of the format described in
the ”Microsoft Virtual Hard Disk (VHD) Image Format Specification”. The
VHD specification is available for anyone to implement under the "Microsoft
Open Specification Promise" described at
http://www.microsoft.com/interop/osp/default.mspx.
The VHD implementation includes support for:
1) Fixed sized disks
2) Dynamically expanding disks
and 3) Differencing Disks.
Dynamically expanding disks don’t change their “Virtual Size”, but they
don’t consume disk space on the containing storage until the virtual
sectors in the disk are actually written to (i.e. an RA81 or RA92 VHD
with a VMS installed on it may initially only contain 30+ MB of files,
and the resulting VHD will be 30+ MB). The VHD format contains meta data
which describes the virtual device. Amongst this meta data is the simh
device type which the VHD was originally created as. This metadata is
therefore available whenever that VHD is attached to an emulated disk
device in the future so the device type & size can be automatically be
configured.
Sim_disk_attach is used by device emulations to attach a simh/vhd/raw
device to a simulated device. The following simh command switches
are used by the sim_disk_attach API:
-R Attach Read Only.
-E Must Exist (if not specified an attempt to create the
indicated virtual disk will be attempted).
-F Open the indicated disk container in a specific format
(default is to autodetect VHD defaulting to simh if the
indicated container is not a VHD).
-X When creating a VHD, create a fixed sized VHD (vs a
Dynamically expanding one).
-C Create a VHD and copy its contents from another disk
(simh, VHD, or RAW format).
-D Create a Differencing VHD (relative to an already
existing VHD disk)
Examples:
sim> show rq
RQ, address=20001468-2000146B*, no vector, 4 units
RQ0, 159MB, not attached, write enabled, RD54, autosize, SIMH format
RQ1, 159MB, not attached, write enabled, RD54, autosize, SIMH format
RQ2, 159MB, not attached, write enabled, RD54, autosize, SIMH format
RQ3, 409KB, not attached, write enabled, RX50, autosize, SIMH format
sim> atta rq0 RA81.vhd
sim> show rq0
RQ0, 456MB, attached to RA81.vhd, write enabled, RA81, autosize, VHD format
sim> set rq2 ra92
sim> att rq2 -f vhd RA92.vhd
RQ2: creating new file
sim> sho rq2
RQ2, 1505MB, attached to RA92.vhd, write enabled, RA92, autosize, VHD format
sim> ! dir RA92.vhd
Volume in drive H is New Volume
Volume Serial Number is F8DE-510C
Directory of H:\Data
04/14/2011 12:57 PM 5,120 RA92.vhd
1 File(s) 5,120 bytes
0 Dir(s) 3,074,412,544 bytes free
sim> atta rq3 -c RA92-1.vhd RA92.vhd
sim> atta rq3 -c RA92-1.vhd RA92.vhd
RQ3: creating new virtual disk 'RA92-1.vhd'
RQ3: Copied 1505MB. 99% complete.
RQ3: Copied 1505MB. Done.
sim> sh rq3
RQ3, 1505MB, attached to RA92-1.vhd, write enabled, RA92, autosize, VHD format
sim> ! dir RA92*
Volume in drive H is New Volume
Volume Serial Number is F8DE-510C
Directory of H:\Data
04/14/2011 01:12 PM 5,120 RA92-1.vhd
04/14/2011 12:58 PM 5,120 RA92.vhd
2 File(s) 10,240 bytes
0 Dir(s) 3,074,404,352 bytes free
sim> sho rq2
RQ2, 1505MB, not attached, write enabled, RA92, autosize, VHD format
sim> set rq2 ra81
sim> set rq2 noauto
sim> sho rq2
RQ2, 456MB, not attached, write enabled, RA81, noautosize, VHD format
sim> set rq2 format=simh
sim> sho rq2
RQ2, 456MB, not attached, write enabled, RA81, noautosize, SIMH format
sim> atta rq2 -c RA81-Copy.vhd VMS055.dsk
RQ2: creating new virtual disk 'RA81-Copy.vhd'
RQ2: Copied 456MB. 99% complete.
RQ2: Copied 456MB. Done.
sim> sho rq2
RQ2, 456MB, attached to RA81-Copy.vhd, write enabled, RA81, noautosize, VHD format
sim> det rq2
sim> ! dir RA81-Copy.vhd
Volume in drive H is New Volume
Volume Serial Number is F8DE-510C
Directory of H:\Data
04/14/2011 01:22 PM 178,304,512 RA81-Copy.vhd
1 File(s) 178,304,512 bytes
0 Dir(s) 2,896,097,280 bytes free
sim> ! dir VMS055.dsk
Volume in drive H is New Volume
Volume Serial Number is F8DE-510C
Directory of H:\Data
03/08/2011 01:42 PM 403,663,872 VMS055.dsk
1 File(s) 403,663,872 bytes
0 Dir(s) 2,896,097,280 bytes free
sim>
The makefile now works for Linux and most Unix's. However, for Solaris
and MacOS, you must first export the OSTYPE environment variable:
> export OSTYPE
> make
Otherwise, you will get build errors.
1. New Features
1.1 3.8-0
1.1.1 SCP and Libraries
- BREAK, NOBREAK, and SHOW BREAK with no argument will set, clear, and
show (respectively) a breakpoint at the current PC.
1.1.2 GRI
- Added support for the GRI-99 processor.
1.1.3 HP2100
- Added support for the BACI terminal interface.
- Added support for RTE OS/VMA/EMA, SIGNAL, VIS firmware extensions.
1.1.4 Nova
- Added support for 64KW memory (implemented in third-party CPU's).
1.1.5 PDP-11
- Added support for DC11, RC11, KE11A, KG11A.
- Added modem control support for DL11.
- Added ASCII character support for all 8b devices.
1.2 3.8-1
1.2.1 SCP and libraries
- Added capability to set line connection order for terminal multiplexers.
1.2.2 HP2100
- Added support for 12620A/12936A privileged interrupt fence.
- Added support for 12792C eight-channel asynchronous multiplexer.
1.3 3.8-2
1.3.1 1401
- Added "no rewind" option to magtape boot.
1.3.2 PDP-11
- Added RD32 support to RQ
- Added debug support to RL
1.3.3 PDP-8
- Added FPP support (many thanks to Rick Murphy for debugging the code)
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
The makefile now works for Linux and most Unix's. Howevr, for Solaris
and MacOS, you must first export the OSTYPE environment variable:
> export OSTYPE
> make
Otherwise, you will get build errors.
1. New Features
1.1 3.8-0
1.1.1 SCP and Libraries
- BREAK, NOBREAK, and SHOW BREAK with no argument will set, clear, and
show (respectively) a breakpoint at the current PC.
1.1.2 GRI
- Added support for the GRI-99 processor.
1.1.3 HP2100
- Added support for the BACI terminal interface.
- Added support for RTE OS/VMA/EMA, SIGNAL, VIS firmware extensions.
1.1.4 Nova
- Added support for 64KW memory (implemented in third-party CPU's).
1.1.5 PDP-11
- Added support for DC11, RC11, KE11A, KG11A.
- Added modem control support for DL11.
- Added ASCII character support for all 8b devices.
1.2 3.8-1
1.2.1 SCP and libraries
- Added capability to set line connection order for terminal multiplexers.
1.2.2 HP2100
- Added support for 12620A/12936A privileged interrupt fence.
- Added support for 12792C eight-channel asynchronous multiplexer.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
1. New Features
1.1 3.7-0
1.1.1 SCP
- Added SET THROTTLE and SET NOTHROTTLE commands to regulate simulator
execution rate and host resource utilization.
- Added idle support (based on work by Mark Pizzolato).
- Added -e to control error processing in nested DO commands (from
Dave Bryan).
1.1.2 HP2100
- Added Double Integer instructions, 1000-F CPU, and Floating Point
Processor (from Dave Bryan).
- Added 2114 and 2115 CPUs, 12607B and 12578A DMA controllers, and
21xx binary loader protection (from Dave Bryan).
1.1.3 Interdata
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state.
1.1.4 PDP-11
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (WAIT instruction executed).
- Added TA11/TU60 cassette support.
1.1.5 PDP-8
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
- Added TA8E/TU60 cassette support.
1.1.6 PDP-1
- Added support for 16-channel sequence break system.
- Added support for PDP-1D extended features and timesharing clock.
- Added support for Type 630 data communications subsystem.
1.1.6 PDP-4/7/9/15
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
1.1.7 VAX, VAX780
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (more than 200 cycles at IPL's 0, 1, or 3 in kernel mode).
1.1.8 PDP-10
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (operating system dependent).
- Added CD20 (CD11) support.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
The source set has been extensively overhauled. For correct
viewing, set Visual C++ or Emacs to have tab stops every 4
characters.
1. New Features
1.1 3.5-0
1.1.1 All Ethernet devices
- Added Windows user-defined adapter names (from Timothe Litt)
1.1.2 Interdata, SDS, HP, PDP-8, PDP-18b terminal multiplexors
- Added support for SET <unit>n DISCONNECT
1.1.3 VAX
- Added latent QDSS support
- Revised autoconfigure to handle QDSS
1.1.4 PDP-11
- Revised autoconfigure to handle more cases
1.2 3.5-1
No new features
1.3 3.5-2
1.3.1 All ASCII terminals
- Most ASCII terminal emulators have supported 7-bit and 8-bit
operation; where required, they have also supported an upper-
case only or KSR-emulation mode. This release adds a new mode,
7P, for 7-bit printing characters. In 7P mode, non-printing
characters in the range 0-31 (decimal), and 127 (decimal), are
automatically suppressed. This prevents printing of fill
characters under Windows.
The printable character set for ASCII code values 0-31 can be
changed with the SET CONSOLE PCHAR command. Code value 127
(DELETE) is always suppressed.
1.3.2 VAX-11/780
- First release. The VAX-11/780 has successfully run VMS V7.2. The
commercial instructions and compatability mode have not been
extensively tested. The Ethernet controller is not working yet
and is disabled.
2. Bugs Fixed
2.1 3.5-0
2.1.1 SCP and libraries
- Trim trailing spaces on all input (for example, attach file names)
- Fixed sim_sock spurious SIGPIPE error in Unix/Linux
- Fixed sim_tape misallocation of TPC map array for 64b simulators
2.1.2 1401
- Fixed bug, CPU reset was clearing SSB through SSG
2.1.3 PDP-11
- Fixed bug in VH vector display routine
- Fixed XU runt packet processing (found by Tim Chapman)
2.1.4 Interdata
- Fixed bug in SHOW PAS CONN/STATS
- Fixed potential integer overflow exception in divide
2.1.5 SDS
- Fixed bug in SHOW MUX CONN/STATS
2.1.6 HP
- Fixed bug in SHOW MUX CONN/STATS
2.1.7 PDP-8
- Fixed bug in SHOW TTIX CONN/STATS
- Fixed bug in SET/SHOW TTOXn LOG
2.1.8 PDP-18b
- Fixed bug in SHOW TTIX CONN/STATS
- Fixed bug in SET/SHOW TTOXn LOG
2.1.9 Nova, Eclipse
- Fixed potential integer overflow exception in divide
2.2 3.5-1
2.2.1 1401
- Changed character encodings to be compatible with Pierce 709X simulator
- Added mode for old/new character encodings
2.2.2 1620
- Changed character encodings to be compatible with Pierce 709X simulator
2.2.3 PDP-10
- Changed MOVNI to eliminate GCC warning
2.2.4 VAX
- Fixed bug in structure definitions with 32b compilation options
- Fixed bug in autoconfiguration table
2.2.5 PDP-11
- Fixed bug in autoconfiguration table
2.3 3.5-2
2.3.1 PDP-10
- RP: fixed drive clear not to clear disk address
2.3.2 PDP-11 (VAX, VAX-11/780, for shared peripherals)
- HK: fixed overlap seek interaction with drive select, drive clear, etc
- RQ, TM, TQ, TS, TU: widened address display to 64b when USE_ADDR64 option selected
- TU: changed default adapter from TM02 to TM03 (required by VMS)
- RP: fixed drive clear not to clear disk address
- RP, TU: fixed device enable/disable to enabled/disable Massbus adapter as well
- XQ: fixed register access alignment bug (found by Doug Carman)
2.3.3 PDP-8
- RL: fixed IOT 61 decoding bug (found by David Gesswein)
- DF, DT, RF: fixed register access alignment bug (found by Doug Carman)
2.3.4 VAX
- Fixed CVTfi to trap on integer overflow if PSW<iv> is set
- Fixed breakpoint detection when USE_ADDR64 option selected
The source set has been extensively overhauled. For correct
viewing, set Visual C++ or Emacs to have tab stops every 4
characters.
1. New Features in 3.4-1
1.1 All Ethernet devices
- Added Windows user-defined adapter names (from Timothe Litt)
1.2 Interdata, SDS, HP, PDP-8, PDP-18b terminal multiplexors
- Added support for SET <unit>n DISCONNECT
1.3 VAX
- Added latent QDSS support
- Revised autoconfigure to handle QDSS
1.4 PDP-11
- Revised autoconfigure to handle more casees
2. Bugs Fixed in 3.4-1
2.1 SCP and libraries
- Trim trailing spaces on all input (for example, attach file names)
- Fixed sim_sock spurious SIGPIPE error in Unix/Linux
- Fixed sim_tape misallocation of TPC map array for 64b simulators
2.2 1401
- Fixed bug, CPU reset was clearing SSB through SSG
2.3 PDP-11
- Fixed bug in VH vector display routine
- Fixed XU runt packet processing (found by Tim Chapman)
2.4 Interdata
- Fixed bug in SHOW PAS CONN/STATS
- Fixed potential integer overflow exception in divide
2.5 SDS
- Fixed bug in SHOW MUX CONN/STATS
2.6 HP
- Fixed bug in SHOW MUX CONN/STATS
2.7 PDP-8
- Fixed bug in SHOW TTIX CONN/STATS
- Fixed bug in SET/SHOW TTOXn LOG
2.8 PDP-18b
- Fixed bug in SHOW TTIX CONN/STATS
- Fixed bug in SET/SHOW TTOXn LOG
2.9 Nova, Eclipse
- Fixed potential integer overflow exception in divide
1. New Features in 3.3-2
1.1 SCP and Libraries
- Added ASSERT command (from Dave Bryan)
1.2 PDP-11, VAX
- Added RA60, RA71, RA81 disks
2. Bugs Fixed in 3.3-2
2.1 H316
- Fixed IORETURN macro
- PT: fixed bug in OCP '0001 (found by Philipp Hachtmann)
- MT: fixed error reporting from OCP (found by Philipp Hachtmann)
2.2 Interdata 32b
- Fixed branches to mask new PC (from Greg Johnson)
2.3 PDP-11
- Fixed bugs in RESET for 11/70 (reported by Tim Chapman)
- Fixed bug in SHOW MODEL (from Sergey Okhapkin)
- Made SYSID variable for 11/70 (from Tim Chapman)
- Fixed MBRK write case for 11/70 (from Tim Chapman)
- RY: fixed bug in boot code (reported by Graham Toal)
2.4 VAX
- Fixed initial state of cpu_extmem
2.5 HP2100 (from Dave Bryan)
- Fixed missing MPCK on JRS target
- Removed EXECUTE instruction (is NOP in actual microcode)
- Fixed missing negative overflow renorm in StoreFP
2.6 I1401
- Fixed bug in line printer write line (reported by Van Snyder)
RESTRICTION: The HP DS disk is not debugged. DO NOT enable this
feature for normal operations.
WARNING: Massive changes in the PDP-11 make all previous SAVEd
file obsolete. Do not attempt to use a PDP-11 SAVE file from a
prior release with V3.3!
1. New Features in 3.3
1.1 SCP
- Added -p (powerup) qualifier to RESET
- Changed SET <unit> ONLINE/OFFLINE to SET <unit> ENABLED/DISABLED
- Moved SET DEBUG under SET CONSOLE hierarchy
- Added optional parameter value to SHOW command
- Added output file option to SHOW command
1.2 PDP-11
- Separated RH Massbus adapter from RP controller
- Added TU tape support
- Added model emulation framework
- Added model details
1.3 VAX
- Separated out CVAX-specific features from core instruction simulator
- Implemented capability for CIS, octaword, compatibility mode instructions
- Added instruction display and parse for compatibility mode
- Changed SET CPU VIRTUAL=n to SHOW CPU VIRTUAL=n
- Added =n optional parameter to SHOW CPU HISTORY
1.4 Unibus/Qbus simulators (PDP-11, VAX, PDP-10)
- Simplified DMA API's
- Modified DMA peripherals to use simplified API's
1.5 HP2100 (all changes from Dave Bryan)
CPU - moved MP into its own device; added MP option jumpers
- modified DMA to allow disabling
- modified SET CPU 2100/2116 to truncate memory > 32K
- added -F switch to SET CPU to force memory truncation
- modified WRU to be REG_HRO
- added BRK and DEL to save console settings
DR - provided protected tracks and "Writing Enabled" status bit
- added "parity error" status return on writes for 12606
- added track origin test for 12606
- added SCP test for 12606
- added "Sector Flag" status bit
- added "Read Inhibit" status bit for 12606
- added TRACKPROT modifier
LPS - added SET OFFLINE/ONLINE, POWEROFF/POWERON
- added fast/realistic timing
- added debug printouts
LPT - added SET OFFLINE/ONLINE, POWEROFF/POWERON
PTR - added paper tape loop mode, DIAG/READER modifiers to PTR
- added PV_LEFT to PTR TRLLIM register
CLK - modified CLK to permit disable
1.6 IBM 1401, IBM 1620, Interdata 16b, SDS 940, PDP-10
- Added instruction history
1.7 H316, PDP-15, PDP-8
- Added =n optional value to SHOW CPU HISTORY
2. Bugs Fixed in 3.3
2.1 SCP
- Fixed comma-separated SET options (from Dave Bryan)
- Fixed duplicate HELP displays with user-specified commands
2.2 PDP-10
- Replicated RP register state per drive
- Fixed TU to set FCE on short record
- Fixed TU to return bit<15> in drive type
- Fixed TU format specification, 1:0 are don't cares
- Fixed TU handling of TMK status
- Fixed TU handling of DONE, ATA at end of operation
- Implemented TU write check
2.3 PDP-11
- Replicated RP register state per drive
- Fixed RQ, TQ to report correct controller type and stage 1 configuration
flags on a Unibus system
- Fixed HK CS2<output_ready> flag
2.4 VAX
- Fixed parsing of indirect displacement modes in instruction input
2.5 HP2100 (all fixes from Dave Bryan)
CPU - fixed S-register behavior on 2116
- fixed LIx/MIx behavior for DMA on 2116 and 2100
- fixed LIx/MIx behavior for empty I/O card slots
DP - fixed enable/disable from either device
- fixed ANY ERROR status for 12557A interface
- fixed unattached drive status for 12557A interface
- status cmd without prior STC DC now completes (12557A)
- OTA/OTB CC on 13210A interface also does CLC CC
- fixed RAR model
- fixed seek check on 13210 if sector out of range
DQ - fixed enable/disable from either device
- shortened xtime from 5 to 3 (drive avg 156KW/second)
- fixed not ready/any error status
- fixed RAR model
DR - fixed enable/disable from either device
- fixed sector return in status word
- fixed DMA last word write, incomplete sector fill value
- fixed 12610 SFC operation
- fixed current-sector determination
IPL - fixed enable/disable from either device
LPS - fixed status returns for error conditions
- fixed handling of non-printing characters
- fixed handling of characters after column 80
- improved timing model accuracy for RTE
LPT - fixed status returns for error conditions
- fixed TOF handling so form remains on line 0
SYS - fixed display of CCA/CCB/CCE instructions
2.5 PDP-15
FPP - fixed URFST to mask low 9b of fraction
- fixed exception PC setting
