- Dear TIP Users,
-
You will shortly be sent a revised version of the "TIP User's
- Guide." Besides now having a loose leaf format, mainly descriptions
-
- of new commands have been added. Appendix B will be an alphabetical
-
- list of all TIP commands. The new commands are:
-
@BINARY INPUT START
@BINARY INPUT END
@BINARY OUTPUT START
@BINARY OUTPUT END
@CLEAR DEVICE WILD
@CLEAR INSERT LINEFEED
@INSERT LINEFEED
@SEND COMMAND
@RECEIVE FROM WILD
@SEND TO WILD
@SET DEVICE WILD
@MAG ABORT
@MAG BACKSPACE FILE
@MAG BACKSPACE RECORD
@MAG READ FILE
@MAG READ RECORD
@MAG SETUP COPY
@MAG SPACE FILE
@MAG SPACE RECORD
@MAG UNLOAD
@MAG WRITE EOF
@MAG WRITE TAPE
- The MAG commands are, of course, not relevant to users of TIPs without
-
- the magnetic tape option.
-
A TIP system including the above commands has been in operation
- since late June. We think this system is a substantial improvement
-
- over previous versions.
-
[Page 1]
-
In case you've not been keeping track, there are now eleven TIPs
- in the ARPA Network. These are ETAC, GWC, AMES, ARPA, MITRE, NBS,
-
- BBN, USC, NOAA, ROME, and SAAC. Also, a TIP will soon be installed at
-
- CCA.
-
I'll now briefly discuss a number of topics I think may be
- interesting to you.
-
Getting TIP status information. As we develop new features for
- the TIP and fix bugs, we are continually releasing new versions of the
-
- TIP program. We do this by just reloading your TIP when you're not
-
- looking (i.e., when no one is using your TIP). In the future we will
-
- notify you whenever a new version of the TIP program is loaded into
-
- your TIP by adding a tiny "status message" to the "HELLO" you get when
-
- you "log onto" the TIP. This status message will usually be merely
-
- the TIP's version number; however, occasionally the message will
-
- indicate (by typing "NEWS") that there is some news about the TIP's
-
- status which you should read before continuing your session with the
-
- TIP. The NEWS can be retrieved by typing the command @NEWS which will
-
- ICP to a special socket at BBN's TENEX or PDP-1D which will print the
-
- news. Of course, either of these systems may sometimes be down, but
-
- we won't worry about the problem until we see how serious it is.
-
To whom to complain or make suggestions. Many of you have had
- occasion to complain about the operation of your TIP system or to make
-
- suggestions for its improvement. All too frequently, however, these
-
- complaints have been directed to the Host system you are using from
-
- the TIP instead of to us. BBN maintains a Network Control Center
-
- which is always manned. Its telephone number is 617-661-0100. All
-
- TIP problems should be reported immediately to the Network Control
-
- Center. If you have a suggestion for a new command, or if you think
-
- you've found a subtle bug in the TIP program, ask to talk to Dave
-
- Walden or Bernie Cosell when you call the Network Control Center.
-
Device buffers. In general, each TIP MLC port has a different
- size buffer allocated to it and therefore to the device connected to
-
- the port. Devices which operate at higher speeds, of course, require
-
- larger buffers, especially output buffers. If you need more buffering
-
- than you have (frequently indicated by output coming in short bursts),
-
- try to arrange with whomever is locally responsible for the TIP you're
-
- using to come in through a port with a larger buffer allocation. If
-
- necessary, this person can arrange with us to specially tailor the
-
- buffer allocation for your TIP.
-
[Page 2]
-
There are presently only about 2500 characters of buffers
- available for the TIPs terminal devices. Since each device has an
-
- input buffer and two output buffers (output is double buffered), each
-
- of the 63 devices has available an average of about 13 charac- ters
-
- for input and 13 characters for each output buffer. Since there is
-
- continual pressure for new features in the TIP and for old features to
-
- work more conveniently, the space available for device buffers is
-
- steadily decreasing. There seem to be two ways to increase the space
-
- available for device buffers; the first is to get more core memory;
-
- the second is to modularize the program so that unneeded features can
-
- be removed from particular sites. For instance, the 2741 code and
-
- character conversion tables might be removed from a site at which they
-
- were never used. You always have the option of getting more core for
-
- your TIP; we are presently working on the latter method and should
-
- have it ready in a few months. In the mean time, the space available
-
- for device buffers will probably continue to slowly diminish.
-
The nominal (untailored) buffer sizes are presently about as
- follows:
-
device input (characters) output (characters/buffer)
1-3 60 56
4-7 28 27
8-15 20 20
16-32 12 13
33-63 6 6
Echoing. The TIP's echoing capability has been a controversial
- item in the past. We have recently fixed it up a little and we think
-
- that if you try it now, you'll like it a lot better. Unfortunately,
-
- "@@" is still not echoed correctly very often; this is a bug and we
-
- are going to fix it, but it's hairy to fix.
-
We will shortly be removing three of the ECHO commands (ECHO ALL,
- ECHO HALFDUPLEX, and ECHO NONE) and be slightly changing the meaning
-
- of the two other ECHO commands (ECHO REMOTE and ECHO LOCAL). We will
-
- also add two new ECHO commands (PHYSICAL HALFDUPLEX and PHYSICAL
-
- FULLDUPLEX.) Thus the new set of ECHO commands will be:
-
@PHYSICAL HALFDUPLEX
@PHYSICAL FULLDUPLEX
@ECHO LOCAL
@ECHO REMOTE
[Page 3]
-
- The ECHO LOCAL and ECHO REMOTE commands will probably be ignored for
-
- physical halfduplex devices. Therefore, for physical full- duplex
-
- devices, ECHO LOCAL and ECHO REMOTE will have the effect of declaring
-
- the device to be virtual halfduplex or virtual full- duplex. Devices
-
- which are known to be physical halfduplex (e.g., IBM 2741's) will come
-
- up in physical halfduplex mode. All other devices will come up in
-
- physical fullduplex mode and local echo mode (i.e., virtual halfduplex
-
- mode). Whenever a connection is opened, the TIP will automatically
-
- send off the current virtual echo mode to the server. Whenever a ECHO
-
- LOCAL or ECHO REMOTE command is given, the virtual mode will be
-
- appropriately updated and forwarded to the server. When the Telnet
-
- ECHO (code 132) (=virtual fullduplex) or Telnet NO ECHO (code 131)
-
- (=virtual half- duplex) characters are received by the TIP, it will
-
- follow the following rules:
-
ECHO received and
TIP is physical halfduplex -- NO ECHO sent to server
TIP is virtual halfduplex -- ECHO sent to server and
mode changed to virtual
fullduplex
TIP is virtual fullduplex -- nothing
NO ECHO received and
TIP is physical halfduplex -- nothing
TIP is virtual halfduplex -- nothing
TIP is virtual fullduplex -- NO ECHO sent to server and
mode changed to virtual
halfduplex
- When a connection is broken, devices in physical fullduplex mode will
-
- be reset to virtual halfduplex mode.
-
Some other command changes we are planning to make.
--------------------------------------------------
- 1. PROTOCOL TO LOGIN will be removed. It has been replaced by
-
LOGIN.
- 2. LOGIN will take a parameter, the Host number, so it will not
-
be necessary to give both HOST and LOGIN commands.
Some things which we are presently doing.
----------------------------------------
[Page 4]
-
- 1. When a terminal hangs up, any captured devices will be given
-
back.
- 2. Output to high speed devices will be possible.
-
- 3. Data sets will automatically be hung up when the caller
-
disconnects even though the caller never "logged in".
- 4. 202C modems will work.
-
- 5. Major improvements on the magnetic tape option.
-
- 6. Trying to find the "R half" of the "R T CLOSED" message.
-
- 7. We have received numerous complaints that the TIP once in a
-
while loses an allocate. We will fix this or else demonstrate
it's not the TIP's fault.
Some things we are thinking about.
---------------------------------
- 1. Adding a lower case capability for Model 33 Teletypes.
-
- 2. Adding a mechanism so the TIP's status or a device's status
-
(e.g., its device number) can be obtained by the user.
Each of the above mentioned changes will be preceded by
- notification via the NEWS and we plan to issue frequent updates to the
-
- TIP User's Guide from now on.
-
We are trying hard to improve the TIP. If you've got a
- suggestion (especially if it doesn't take any memory), let me hear
-
- from you.
-
Regards,
< signed "Dave" >
David C. Walden
Bolt Beranek and Newman Inc.
July 11, 1972
[ This RFC was put into machine readable form for entry ]
[ into the online RFC archives by BBN Corp. under the ]
[ direction of Alex McKenzie. 1/97 ]
[Page 5]
-