SAGE@LL.ARPA (06/13/88)
The following item is submitted in response to a number of inquiries
I have received over the net.
Joe Wright, Bridger Mitchell, and I have just completed NZ-COM and
Z3PLUS, new versions of the Z-System that are automatic, universal, and
dynamic. NZ-COM runs on CP/M-2.2 computers; Z3PLUS runs on CP/M-Plus
computers. NZ-COM does run on Apple CP/M cards.
They are automatic in that no installation is required. In particular,
no changes have to be made in the BIOS. There is no need for source code,
editing, assembling, MOVCPM, SYSGEN, or DDT. The Z-System can be removed at
any time by issuing a command that reinstates the user's underlying CP/M
system. Joe Wright invented the basic technique with his Z3-DOT-COM and Z-
COM products several years ago. Bridger Mitchell has (hooray!) extended the
technique to CP/M-Plus systems, and many very substantial enhancements have
been added.
The new systems are universal in that system modules can be provided in a
file format that can be used on any system with memory allocated for that
module. Bridger Mitchell invented a new relocatable file format which we
call ZRL, for Z-system ReLocatable. It is based on the seldom-used named
common facility supported in advanced assemblers. For example, the new
command processor, ZCPR34, can be supplied as a small, binary file (e.g.,
ZCPR34.ZRL) that can be loaded into any CP/M-2.2-based Z-System, no matter
how its memory is configured (Z3PLUS has an equivalent command processor).
There is no longer a need to assemble from source code with a Z3BASE.LIB
file configured to describe the user's particular system. The same is true
for RCPs, FCPs, DOSs, and other code modules.
My contribution to the effort (besides the version 3.4 command processor)
was to make the operating systems dynamic. It is no longer necessary to
make a static, once-and-for-all trade-off between Z-System features and
program memory space. The operating system is now more like an application
program -- it can be changed at any time, even right in the middle of a
multiple command line. It can be changed manually or automatically under
the control of aliases that use the Z-System flow control facility.
Now you can allocate memory (1.5K typically) for an IOP (input/output
package) only when you are actually using an IOP. When a memory-hungry
application program is to be run, you can drop the two largest buffers, the
RCP and IOP, which usually take 3.5K of memory. If you need still more
room, you can drop the NDR and FCP. You can make a minimum Z-System that
takes only 1.0K and still provides its most important features. If your
application requires absolutely every available byte of memory, you can drop
back to CP/M. Using SUBMIT, even this process can be automated! The Z-
System can disappear, an application can run under standard CP/M, and the Z-
System can be reestablished, all automatically as a result of a single user
command! You never even know that Z-System was gone.
With NZ-COM's system definition utility MKZCM (MaKe Z-Com) you can define
the sizes of the following modules: CCP, DOS, BIOS, IOP, RCP (resident
command package), FCP (flow command package), NDR (named directory
register), shell stack, and an all-purpose user buffer. The latter can be
used for "above-BIOS" items like DateStamper, BYE, special drivers, and so
on. In the case of the shell stack, you can define both the size and number
of stack entries supported. And, by the way, that was not a misprint above
-- you can define systems with nonstandard CCP, DOS, and BIOS sizes. This
allows for some rather interesting experiments and configurations. Z3PLUS
allows similar capabilities.
You can now have several versions of command processor or DOS and load a
new one with a simple command. NZCOM is supplied with four significant
variants of the command processor; Z3PLUS includes two versions, one of
which puts the time in the prompt. Similarly, with NZ-COM you can switch
between ZRDOS (supplied with NZ-COM) and other versions of the DOS now (or
soon) available, such as P2DOS, Z80DOS, ZSDOS, and ZDDOS. (Z3PLUS uses the
CP/M-Plus DOS.)
Each product includes an extensive manual (more than 70 pages in 'IBM'
format binder, written by me and Bridger Mitchell) covering the particular
product and Z-System in general. There are many examples and hints. Each
product is priced at $69.95 for the standard version including the necessary
operating system files and a minimum set of Z utilities. NZ-COM is offered
in a version with some sources (including the source to ZCPR34) at $99.95.
Eventually there will probably be some higher priced versions that include a
more extensive set of Z utilities on diskette. For those who have access to
Z-Nodes, Royal Oak, or Simtel20, there will be no need to spend the extra
money on these versions. For those who for some unusual reason cannot use
NZ-COM (or for the stubborn who insist on an inferior, manually installed
system), the source to ZCPR34 is available separately at $49.95.
For those who have not heard, Joe Wright's Alpha Systems has taken over
the marketing of Z-System from Echelon, which is essentially out of
business. Orders for the new products can be placed with any of the
following sources:
Alpha Systems (Joe Wright)
711 Chatsworth Place
San Jose, CA 95128
408-297-5583 (voice)
Sage Microsystems East
1435 Centre Street
Newton Centre, MA 02159
617-965-3552 (voice -- but a recorder except evenings, since my wife
is now away [as I will be from 6/23 to 7/14])
617-965-7259 (modem, 24 hr, pw=DDT, VISA/MC orders
and download delivery)
Plu*Perfect Systems (Bridger Mitchell, for Z3PLUS)
410 23rd Street
Santa Monica, CA 90402