GUBBINS@RADC-TOPS20.ARPA (12/21/83)
From: Gern <GUBBINS@RADC-TOPS20.ARPA>
H/Z-100 Newsletter Volume 1 Issue 1
January 1984
All the world's an analog stage,
and digital circuits play only bit parts.
------------------------------------------------------------------------
This is the first issue of the H/Z-100 Newsletter, an edited compilation
from a variety of random sources. With the Zenith Z-100 being made the
Air Force / Navy Standard Microcomputer System under AFCAC Project 229,
the generous offer of the GSA prices to all DoD employees through GEA,
and Clarkson's 800+ entering freshman class having one per student, the
need to unify the H/Z-100 community has arisen. This is my attempt to
do so. I am David Michael Gubbins (College nickname - Gern), a May '83
graduate of Clarkson College in Electrical & Computer Engineering. I
bought the standard single drive 192K Clarkson Issue Machine & Software
through the deal extended to upperclassmen. A small part of my job at
RADC concerns the evaluations of the Z-100, and I attended the Air Force
Small Computer Conference in Montgomery, Alabama (25-27 OCT 83) where
I once again had all my questions answered by Mr. Donald Moffet (the
President of Zenith Data Systems) and his technical and marketing staff.
If there is enough support and resources, I would like to start and
maintain an INFO-HZ100 Digest, a rival to INFO-IBMPC Digest. Useful
knowledge and items generated from the digests and other sources would
be periodically edited into a Newletter (such as this) and distributed
to both network and non-network interested groups (ie. Clarkson College
of Technology Zenith Users Group (CCTZUG), etc...).
Several items used in this newsletter have been extracted from CCTZUG's
first two newsletters, of which I was Editor.
Any comments, suggestions, help, knowledge, software, ideas, etc...
would be greatly appreciated. Thanks.
------------------------------------------------------------------------
There is a warning on page 4 of older versions of the low profile
Z-100 Unpacking Instructions which states that during use, not to place
the monitor on top of the computer. This is in error and can be ignored.
Prototype machines did not have disk drive shields, hence the warning.
Production machines are shielded and the monitor can be safely placed on
the top of the machine. Note that the monitor's fly-back transformer
in both the all-in-one and low-profile models, throws a slight electro-
magnetic field to the left. Do not keep disks to the left of a turned
on monitor. This is true for almost all monitors and television sets.
Do NOT close the disk drive doors when the Z-100 is not being used.
This will cause the two ceramic read/write heads to hit together. Be
sure to insert the cardboard shipment disks and close the drive doors
when moving or transporting the computer.
Substantial wear will occur to disks if being accessed continually
for an extended period of time (several hours). Dual disk users should
note that both disks spin even if only one disk is accessed. If only
one disk is being used to collect real-time data for more that an hour,
open the unused drive's door to prevent the heads from wearing down the
disk tracks.
------------------------------------------------------------------------
The Z-100 optimizes the scrolling speed of the screen when color is
not being used in the system. The computer must be told when Z-BASIC
will be working with color on the screen so that it can use the proper
scrolling method. Otherwise, the optimized screen scrolling action will
cause the color in the display to be lost under certain circumstances.
To make sure that your programs are going to operate correctly, place
the following line of code near the beginning of each affected program:
10 CLS:COLOR 1,0:PRINT"":COLOR 7,0:LOCATE 1,1:PRINT"":LOCATE 1,1
------------------------------------------------------------------------
Notes on BASIC FOR/NEXT loops - Be careful of reusing loop counters:
10 FOR Y... Remember: Restarting a loop
20 FOR X... kills all loops inside the
30 NEXT X non-completed loop.
40 IF Condition THEN 60
50 NEXT Y <= If Condition is met, Y loop
will not be completed.
60 FOR X...
70 FOR Y... <= Thinks old Y is restarted
80 NEXT Y (Killing old inside loops -
90 NEXT X X) Hence only active loop
defined is Y.
NEXT without FOR Error in 90
------------------------------------------------------------------------
Systems Engineering Postulate: The quality of the design and components
is proportional to the size and weight of the power supply. Think of
this whenever you become annoyed by the whirr of the Z-100's cooling
fan. The IBM-PC/XT's fan is much worse, and the power supplies are
by far inferior to that of the Z-100 - Zenith should know, they built
them that way. Zenith is one of the two suppliers of power supply/fan
units for the IBM machines.
------------------------------------------------------------------------
My computer went down yesterday, so I simulated it with a piece of paper
and pencil.
------------------------------------------------------------------------
The following .ASM file is a dumb terminal program for those who want
to get up quick at minimum (ie zero) cost. Assemble, link, and convert
it to a .COM file for use under Z-DOS.
TITLE STERM" - Simple terminal program
Page ,132
.XLIST
INCLUDE DEFCHR.ASM
INCLUDE DEFMS.ASM
.LIST
PGMSEG SEGMENT
ASSUME CS:PGMSEG,SS:PGMSEG,DS:PGMSEG,ES:NOTHING
ORG 100H
RECE:
MOV AH,CHR_STATUS
MOV AL,CHR_SFGS
CALL BIOS_AUXFUNC ; check status of auxin
AND AH,CHRS_RXR ; and see if char ready
JZ SHORT XMIT ; go check keyboard if nothing coming in
CALL BIOS_AUXIN ; else get character
CALL BIOS_CONOUT ; and put it on screen
XMIT:
MOV AH,CHR_STATUS
MOV AL,CHR_SFGS
CALL BIOS_CONFUNC ; go check status of keyboard
AND AH,CHRS_RXR ; check for char ready from keboard
JZ RECE ; loop if no key ready
CALL BIOS_CONIN ; else go get char from keyboard
CALL BIOS_AUXOUT ; and transmit char
JMP SHORT RECE
PGMSEG ENDS
END RECE
From: harpo!floyd!vax135!cornell!uw-beaver!ssc-vax!bruce@ucb-vax
------------------------------------------------------------------------
A look at the Zenith model numbering system:
Each model number lets you see at a glance the machine's main features.
The model number is broken down into PREFIX-BODY-SUFFIX as follows:
Prefix First Letter (Model) - Z = Zenith
H = Heath
Prefix Second Letter (Disk Drives) - F = 48 TPI Double-Sided
X = Customer OEM System
H = 96 TPI Double-Sided
W = Winchester
E = 48 TPI Single-Sided
Prefix Third Letter (CRT) - No Letter = Green
W = White
A = Amber
C = Color
Body Number - 100 = Low Profile Monocolor Video
110 = Low Profile Color Video
120 = All-In-One Monocolor Video
130 = All-In-One Color Video
Suffix First Number - Number Of 64K Banks Of User RAM
Suffix Second Number - Number Of Disk Drives
So, if the model number is ZF-120-22, it means a Zenith wired model,
with two 48 TPI disk drives, a white CRT, all-in-one with monochrome
video, and two banks of 64KByte user RAM (128KByte).
------------------------------------------------------------------------
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