Date : Sun, 22 Jan 1984 23:17:09 EST
From : Keith Petersen <w8sdz@brl>
Subject: MDM719 now available
MDM719, the latest version in the MODEM7 series, is now available
on SIMTEL20 in the MICRO:<CPM.MODEM7> directory and temporarily
on MIT-MC in the FJW; directory. The file names are:
On SIMTEL20 On MIT-MC
MDM719.ASM MDM719 ASM
MDM719.COM MDM719 COM (ITS-Binary format)
MDM719.HEX MDM719 HEX
MDM719.MSG MDM719 MSG (explains recent updates)
M7NM-4.ASM M7NM 4ASM (latest phone number overlay
which also can configure file
transfer buffer size)
It's not necessary to get the latest .ASM file. Get the .HEX or
.COM file and use your present MDM7xx overlay. Remember to SAVE 69
after patching because recent versions are larger than those explained
in the overlay patching instructions.
NOTE: If using the phone number overlay to change
the phone library numbers, be sure to use M7NM-4.ASM.
(previous versions of M7NM will not work with
this new version, as the file transfer buffer
is now optional length, nominally set for 4k.)
CHANGES FOR MDM719
Fixed Irv's error in GETACK routine which prevented the robust
improvement (added by Bob Plouffe) from working. Changed ACKNAK to NO
so default will require valid NAK rather than non-ACK. This is part of
the robust improvements, NOT because of any special ArpaNet require-
ment. Changed SHOWHEX to true for distribution version so users would
have HEX and DECIMAL reporting while transferring files (most users
have told me they prefer to see both). Changed PMMI dialing pulse
default to 10pps which most exchanges will accept. (This can be set to
other pulse rates in the user overlay).
- Keith Petersen, W8SDZ
CHANGES FOR MDM718
Code added to the auto-dial routine for the new Anchor 300/1200
modem which are selling at discount houses for $270 or so. Computer
now beeps continuously anytime a connection is made to attract the
operator's attention. Made the file transfer buffer length separate
from that of the ASCII capture buffer (which remains 16k, one file-
extent). Although the file transfer buffer has been 16k for well over
a year, some of the newer floppy disk systems are quite slow and
timeout errors could occur. The file transfer buffer size is set by
default to 4k (32 records, 20H). It can be set at assembly time if
using the entire MDM718.ASM file, or can be set in a few seconds with
DDT by changing byte 0CFFH. The number library is now fully automatic
to insure it always starts on a new page (such as 0D00H) regardless how
much the auto-dial section is altered. Now responds to either "single
digit" result codes (some Hayes Smartmodem users leave SW2 set that
way) as well as the normal "verbose" result codes.
To change the file transfer buffer size via DDT, change byte 0CFFH:
10 (hex) = 16 records = 2k
20 (hex) = 32 records = 4k
40 (hex) = 64 records = 8K
60 (hex) = 96 records = 12k
80 (hex) = 128 records = 16k
(then SAVE 69 MDM.COM, etc.)
CHANGES FOR MDM717
MDM717 allows characters with parity bit set to be properly
handled during propagation overruns after an X-off. This occurs during
a "save to disk" after the disk buffer fills. (This problem was
noticed on Compuserve which sends some characters with the parity bit
set.)
The disk buffer size was restored to 16k. This is the length of
"one file extent". Even slow floppy disks can store 16k in a reason-
able amount of time. This should remain 16k for distribution copies of
the source code although it can be easily changed to suit the indivi-
dual user's own preference. (It could even be lengthened to 32k if you
like fewer disk operations. This would make the printer buffer
proportionally smaller but most printers are so fast the buffer is
rarely filled in any case.)
Fixed a stack problem introduced in v716 in the "V" flag routine
to allow the user to show ASCII characters on the CRT during a file
transfer.
Fixed the "L" Logon feature so it should be consistent. At times
it would run away without waiting for the echo characters, thus not
correctly displaying the Logon message.
Restored the ACKNAK feature developed for the exclusive use of the
ARPANET networking group. When set normal ("YES") it resends a disk
record after any NON-ACK character is received. This has been the
normal configuration for all RCPM systems using the XMODEM file
transfer program. When set "NO" for ARPANET use, it resends a record
only after a NAK has been received. Other characters are ignored.
Some systems will resend a NAK after a 10-second TIMEOUT. This slows
things considerably, which allows the main frame time to recover if
busy. This tends to run the phone bill higher for RCPM use, but is
necessary for ARPANET to prevent aborting the file transfer too quickly
if the main frame is busy. If a normal TIMEOUT sequence does attempt
to abort the transfer with the ACKNAK equate set to NO, it will ask if
you want to try again or abort. (RCPM systems would have already timed
completely out with 10 consecutive errors, making the question
worthless and misleading. ARPANET does not have a similar feature, and
the user can manually force the transfer to continue.)
- Irv Hoff