README.md
readme.sy Documentation for SY and SYDATE Page 1
The SY (SYstem option) handler is an RT-11 pseudo-handler that contains
only SET and installation code but never installs. It was originally written
by someone in the RT-11 development group at DEC and first appeared on an RT-
11 DECUS SIG tape at the end of 1979. I believe that it was written during
the development of RT-11 V4 and that its original purpose was to disable the
cache on either an 11/70 or an 11/34, so that all memory cycles would appear
on the bus while debugging the system. The date setting function was added
after the cache disable to automatically set the date on a system that was go-
ing up and down like a yo-yo.
I converted the handler from RT-11 V4 format to RT-11 V5.2 format and
added the SET [NO]FORCE code to not modify a system date if it was already
set. This is useful when doing a soft bootstrap after the date has been
changed but before the date has been reset in SY. I found I needed this
when returning to RT-11 from TSX-Plus, since there was no way to update the
date in SY while TSX-Plus was running.
The SET commands supported by the handler are:
SET SY CACHE Leave processor cache enabled on boot (if it exists).
SET SY NOCACHE Disable processor cache on boot (if it exists).
SET SY DATE Save current date in handler for next bootstrap.
SET SY NODATE Set date word in handler to zero.
SET SY FORCE Always set system date on boot, even if set already.
SET SY NOFORCE Only set system date on boot if it is not set.
Note that the term "boot" or "bootstrap" above really means when an attempt
is made to install the handler, either during bootstrapping or through an
INSTAL command. Note that the handler will NEVER actually install.
The SYDATE program was developed when we found we did need to set the
date in SY while TSX-Plus was running. It simulates the effect of "SET SY
DATE" on SY:SY.SYS (assuming that the default bootstrap system is SJ or FB).
It can be called with the "R" or "RUN" commands or in the CCL form. I use
it rather than "SET SY DATE" under RT-11 because it requires less typing.
The files accompanying this document are:
SY.V04 The original source file from the 1979 SIG tape.
SY.MAC The current source file.
SY.SYS SJ/FB handler, no sysgen options.
SYDATE.MAC The current source file.
SYDATE.SAV The runnable program.
Generating either the handler or the program from the MACRO source files
is straight-forward; just assemble and link them. Although current handlers
are normally linked with /NOBITMAP, there is so little code in SY that it
makes no difference whether it is linked with or without this qualifier.
readme.sy Documentation for SY and SYDATE Page 2
Considering how little code really exists in SY, you may find that it is
useful for initializing other devices on your system. Remember that the in-
stallation code will be executed on both hard and soft bootstraps; if you do
not want it to execute more than once, you will need code to check whether the
device has already been initialized.
I have found the date setting to be very useful when I am doing handler
development; I would like to know what additional things you do with it.
Jim Crapuchettes
Omnex Corporation
2483 Old Middlefield Way
Mountain View, CA 94043
(415) 966-8400