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Article #164 (214 is last):
From: xx004@cleveland.Freenet.Edu (Atari SIG)
Newsgroups: freenet.sci.comp.atari.product.8bit.zmag
Subject: Z*Magazine:  6-Jun-89 #160
Reply-To: xx004@cleveland.Freenet.Edu (Atari SIG)
Date: Sat Sep 25 16:13:54 1993


          |  ROVAC ZMAGAZINE  |
          |    Issue  #160    |
          |   June 6, 1989    |
          |Copyright 1989, RII|
          
                 
                
               
                           
                            
                             
 
 
 
        
        |This week in ZMagazine|
        
 


   Atari Announces New Products 
               ZBreak #5

 Summer CES Chicago June 3, 1989 
             <<<< Kirk >>>>

     Hard Disk Hints (Part 2) 
             W. K. Whitton

      The Master Memory Map 
              Jerry Cross

    Electronic Mailbox At Home 
              Bob Fasoldt

                    


 
 |ATARI ANNOUNCES NEW PRODUCTS AT CES|
 

 Z*BREAK #5       EXCLUSIVE CES REPORT

              June 3, 1989

Copyright (C)1989 Rovac Industries, Inc


The following report comes direct from
our ST*ZMAG/Z*Net correspondents Mike
Letchkun and Brian Wilmoth live in
Chicago for the annual Consumer
Electronics Show.

At noon today, June 3, 1989, Sam
Tramiel called a news conference and
announced the release of the first
Atari portable Color Arcade System.
This 3 1/2 inch LED video game system
measures approx 11 X 4 X 2 and weighs
about 1 pound.  16 colors on a
160 X 102 screen.

Retail price is set at $149.95.  Atari
is releasing the product in conjuction
with Epyx and debuts with the following
game cartridges:  Impossible Mission,
Blue Lightning, Time Treasure Chest and
a few others.  The unit has 4 channel
sound and Comlink.   Comlink is an
output via RCA phono jack and allows
simultaneous play with up to 8 portable
units.

The portable game system runs at 16MHZ
with 6 AA batteries.  Another feature
is the ability to press two buttons at
the same time to reverse the screen for
left-handed players.  There were 5
units on hand for show attendees to
play with.  An additional game called 
California Games will be available with
the full four part version.

This announcement has been kept secret
until today's show.  Software prices
will range between $20 and $30.00.

At the Atari Booth, 8-bit software was
shown:  Deflecktor and Xenophobe, along
with the first look at MidiMaze from
Xanth.   This configuration consists of
SIO cables to 3 outputs.  Midi I/O is
dedicated to the game.

The 7800 was on hand with new releases
that include Commando, Tower Topple,
Double Dragon, Jinx, Xenophobe, and
Shooting Arcade.

The 2600 was also shown with Road
Runner, Double Dragon, Rampage, BMX
Simulator, and Radar Lock.

The PC4 286 was shown with the 3 1/2
and 30 meg hard drive.  We were told
that FCC approval is still lacking
because of the case configuration.
However, Atari was still making the
official domestic release at this show.

Lastly, Spectrum Holobyte announced a
new missions disk for Falcon.  They
will be released in July.  The PC and
MAC will be getting attention in the
game area before the ST.  The first
port-over will be VETTE.  VETTE is a
driving simulator which takes you
through the streets of San Fransisco.

                    


  
  |SUMMER CES CHICAGO JUNE 3, 1989  |
  
           
           |by <<<>>>|
           


Atari introduced a new portable COLOR
game system today.  This unit is about
the size of of VCR tape, yet only
weighs one pound, and includes a
built-in 3 1/2 inch color screen.  On
the left side of the unit is a built-in
8 direction joypad, and on the right
side is a set of four buttons for game
control/firing.  An additional option
is the ability to flip the image on the
screen so that the unit can be held
with the joypad in either hand,
allowing for comfortable use by left
handed people.

The following is a list of features:

* 16MHZ (not a typo) 65c02
  microprocessor
* 16 simultaneous colors from a pallet
  of 4096
* Game cards as large as 2 Megabytes
  (current cards at 128K bytes) on the
  size of a credit card
* ComLink: communications port allowing
  up to 8 machines to be linked
  together for simultaneous play
* Headphone jack for private listening
* Runs on 6 AA batteries (about 6-8
  hours) or AC adapter
* 6 games announced for this new
  machine by Eypx

Suggested price: $149

Available by September?

Also at the show were the 80286 8MHZ PC
clone from Atari as well as several
'Portfolio' hand held computers
(however, the portfolio had no specific
display for themselves--they were being
carried by some of the Atari
representatives).

Other than that the display was
composed mainly of 2600s, 7800s, and
XEGSs, and a display of Atari brand
calculators.  A demo of MidiMaze was
being shown on the XEGS, as well as a
version of Tower Toppler.

                    


       
       |HARD DISK HINTS (PART 2)|
       
            
            |W.K. Whitton|
            

    Reprinted from ST-ZMagazine #23


     The Ins and Outs of Interleave
                  or
 "A Thousand and One Practical Uses For
          Thin & Crispy Pizza"


Although there is an abundance of
computers complete with various and
sundry operating systems, one thing is
common to them all.  They all use
magnetic media of some sort (CD systems
notwithstanding!).  They rotate the
media at speeds from 300 rpm all the
way up to 3600 rpm, and disks can
readily be found in sizes from 3 1/2
inches up to 8 inches in diameter.
These systems store their data on these
disks by means of flux changes in the
magnetic coating on the surface of the
media.

The most common material used in the
construction of a floppy disk is
"Mylar", and has a coating of
ferro-magnetic particles implanted on
both sides.  The data is written to
this media in circular patterns, much
the same way a record album is written.
It does does differ somewhat though as
the data on an LP is more like a
spiral, while the data on a disk is
comprised of smaller and smaller
concentric circles.  Another difference
between the two is that the LP spins at
33 R.P.M.; the floppy disk spins at 300
R.P.M. (or in some systems, 360 R.P.M.)
The floppy disk, depending on several
factors, can save from 160 thousand
bytes (called 160K) to almost a million
and a half (1.44 Megabyte).

Another popular storage medium for
computers is the hard drive.  Hard
drives use platters, which are round
just as floppies are, and likewise
contain data on both sides of the
magnetic media.  But, these spin at a
much faster rate (3600 rpm on the
average), possess the ability to hold
quite a bit more data (5 Meg on up to
over 600 Meg), and are not flexible nor
removable as the floppies are.

In the late 70s and early 80s it was
common to see hard drives which had the
capacity of 5 Meg.  These technical
marvels of the day were single platter
mechanisms, and a paltry 160 tracks
compared to today's standard.  Hard
drive technology has greatly advanced
since that time, and it is commonplace
to see advertised multi-platter,
thousand track drives.  These massive
storage devices are ordinary rather
than extraordinary both in price and
availability.  We can safely say that
the computers we now have to use,
abuse, and enjoy, with their "Megs" of
RAM, multiple "Megs" of hard drive
storage space, and much faster CPUs,
such as the Atari Mega ST computer
system with optional hard drives, in
many ways rival the large commercial
systems of the late 70s in cost,
performance, and storage capacity.

In order to understand a little better
what we are going to discuss, you will
need to visualize what the sectors
appear to look like on a disk.  Imagine
going to your local Pizza Hut and
holding a user group lecture.  You
order a large thin and crispy pizza
with everything on it (stop drooling!)
for your demonstration, and tell the
waitress to not cut the pizza.  Take
the pizza cutter and divide the pizza
into 17 equal slices, but leave them in
the tray as they were.  Now, you pull a
bag from under the table.  In it you
have donut cutters you swiped from the
local donut shop.  You proceed to recut
the pizza, starting at the middle with
a tiny round cutter, and proceeding
with a larger diameter cutter each
time.  What we have done thus far is
slice the pizza (into sectors), and cut
it with the donut cutters (into
cylinders or tracks depending on your
vocabulary), and ended up with quite a
few pieces of pizza that resemble
miniature half-moons.  Let us say these
little half-moons of heavenly cuisine
are equal to 512 bytes on your hard
disk.  You could then easily calculate
the total storage capacity of your
storage device by multiplying and using
this formula:  storage capacity = 512 x
total # of sectors.  Now if you really
wanted to go all out, you could have
purchased 4 or 5 pizzas, stacked them
on top of each other, and ended up with
a true approximation of what a
multi-platter hard drive looks like.
If realism was extremely important,
then you could instruct them to put the
toppings on BOTH sides of the pizza
(weird!).  In a real hard drive, each
of these separate platters is read by
its own individual head.  The only
thing I would recommend here is
instructing the Pizza Hut crew to put
your "data concoction" in the
microwave, and order a LARGE pitcher of
pop...while you are waiting, you may
wish to calculate the total storage
capacity of the "crispy drive" you just
constructed.  The formula is:  capacity
(in bytes) = sectors per track X tracks
on each platter X total number of
heads.

Let us leave our pizza analogy behind.
As the hard drive merrily spins along
at 3600 rpm, the sectors are passing by
the read/write head.  The speed at
which the bits pass by is found by
calculating 17 sectors, and 512 bytes
per sector, at a speed of 3600
rpm...hmmm...that comes out to
31,334,400 data bytes per minute, or
4,177,920 data bytes per second.  One
thing you should note is that each
sector contains "control information"
which is in addition to the data you
stored on the device.  Its purpose is
to allow the controller to actually be
able to access the data, so the
real-time data transfer rate is
actually a little higher than what you
calculated (5 Megabits per second is a
very safe guess).

Interleave can be best expressed as the
the sequence of physical sectors on a
hard disk as it relates to the logical
sequence of the sectors.  The
interleave factor (such as 1:1, 4:1
etc.) can be defined as the number of
times the disk must revolve in order to
read all the sectors on the disk, in
order, from the first sector to the
last.  An interleave of 1:1 is the
fastest possible, meaning it reads one
entire track in one revolution of the
platter.  Lets us take a typical
WordWriter II text file, such as the
one comprising this very article.  An
average short article by yours truly is
usually about 5K long.  This means that
this file takes up 10 sectors on the
hard drive, as each sector is 512 bytes
wide.  What is known as the first
logical sector is that part that
contains the first part of our file in
question, while the last logical sector
of course contains the last part of our
text file.  Let us, for illustrative
purposes, say that the first logical
sector happens to be 4,50.  The next
record won't necessarily be 4,51 as you
might suppose, but rather, this is
determined by the interleave of your
hard drive.  If the interleave is 1:1,
then this means the physical sectors
are laid out in such a manner as to
make them equal to the logical sectors.
This means the data would be laid out
like this:

 1_2_3_4_5_6_7_8_9_10_11_12_13_14_15_16

If the interleave is set at 2:1, then
the second logical sector would appear
at 4,52 , the next at 4,54 and so
forth.  The data on an "interleaved
drive" is laid out a bit differently
than 1:1, one drive had the data laid
out like this:

1_10_2_11_3_12_4_13_5_14_6_15_7_16_8_17

Can you guess what interleave this
represents?

Now, if we wrote after sector one,
sector five, and after two we placed
sector (an interleave of 4:1), it will
take 4 revolutions of the platter to
read in all 17 sectors of the drive.
This is not a data rate of 500K, but it
is much, much faster than attempting to
read the same data one sector per
spin!!!  The optimal placing of data on
your hard drive for fastest data
transfer rates is what interleaving is
all about.

Since some computers and controllers
cannot reliably read and write data as
fast as the current interleave is set,
and an interleave that is set wrong
will drastically slow your I/O down,
and in some extreme cases the integrity
of your data may be threatened, this is
an important factor you must give some
thought to in order to get peak
performance from your system.  A good
case is a clone that was just in the
shop I am employed at.  After
completing the repair, I noted the hard
drive acted as if it was extremely
sluggish.  After a few investigative
tricks, I determined that that
interleave, currently at 6:1 or
thereabouts, was not proper for an
optimized system.  I used a fine
utility I received from GEnie, called
Interleave (strange as it may seem), to
change the current value on this
system.  The utility will actually
change the interleave, a sector at a
time, and then replace it on the newly
laid out track.  After 4 hours or so,
that task was completed, and the owner
of the system called back to thank us
for the unbelievable speed increase he
noted!  I remember the words "Better
than new!"  Of course, his drive
formatting software did not attempt to
find out what interleave was best for
his system when the hard drive was
lasted formatted.  Please note that the
program mentioned is for the IBM-type
machines--no similar interleave changer
is available for the ST.

How is the optimal interleave
determined for your system?  If you
purchased your hard drive system
already assembled, such as those
systems from Atari, Supra, and ICD,
then they have determined what is best
for your system.  If you pieced your
system together from various
components, whether purchased locally
or the mail order route, then you were
the one who did it, although quite
possibly, unknowingly!

Finally, since we can not at this time
change the interleave on the Atari ST
(or 8-bit systems, either) other than
by totally reformatting the drive, and
thereby losing all your data, >please<
plan the layout and interleave of your
drive before proceeding with your
original formatting of your hard
drive.  You'll save a lot of time later
on!  (The ST is quite capable of 1:1
interleave...and this setting is used
by ICD and other interfacing
equipment.)

Note: As a matter of information, some
RLL drives does not conform to the 17
sector format, but rather they do
things a bit differently on these
drives/controllers, so not all of the
above information is totally correct in
the case of a few drives of this type.
I'll spare you the details to avoid
confusion!

                    


        
        |THE MASTER MEMORY MAP|
        
            
            |by Jerry Cross|
            

        Reprinted from the June
        Great Lakes Atari Digest


While stumbling around the Disneyland
World of Atari show, I came across an
interesting book at the BEST
Electronics booth.  Big deal, another
Atari book you say?

Have you taken a trip recently to your
local book store in the area mall?
Ever look at the computer book section?
Atari books are extremely scarce.  If
you look really close, stuck someplace
near the top of the shelf, in the
middle of a bunch of Apple books, you
just MIGHT find a manhandled copy of
one of the COMPUTE! books still
available, but I wouldn't bet on it.

If you do find an Atari book, it
usually falls into one of three
categories:  "Strictly Beginner", where
the author simply took common
information from the Atari Basic
handbook and added a few samples;
"Topic Specific" such as machine
language, graphics, or some other topic
that is pretty worthless to a beginning
programmer; and "Hard Core Handbooks"
like Mapping the Atari, De Re Atari, or
other technical handbooks.  This
category goes way over the heads of
beginners.

There are very few good books for an
intermediate programmer, one who is
more than a beginner, but not ready yet to probe the "internals" of computer
programming.  That's why I was so
impressed with this book.

"The Master Memory Map" is very similar
to Mapping the Atari.  Basically, it
looks at how a beginning programmer can
use the POKE command to enhance their
programs to include some of those
special effects and "nifty-keen" tricks
like turning off the break key or
protecting your software.  But unlike
Mapping the Atari, this book was
written in very easy to understand
language, so that beginning programmers
can understand it.

Ask a beginner what a "vector" is.  How
about a "buffer".  No, it's not a naked
swimmer.  The problem with most of the
reference books on the market is that
they assume you already know what these
terms are.  But The Master Memory Map
assumes you don't, so you will get a
lesson each time you come across one of
these strange terms.  This is
especially true in the beginning of the
book, but as you work your way through
the book they slack off the "lessons"
and get into the real use of the
particular memory location.

This book will take the beginning
programmer through most of the
important (and useful) memory
locations, and explain in simple
lessons how they can be used to enhance
their programs.  It will tell you if a
location is for the more advanced user,
but still explains it's use.  By doing
this, the beginner learns how that
memory location is used by the
operating system.  This was not done
with Mapping the Atari, which simply
gave you a brief description of that
memory location.  This can be an
extremely useful lesson for those folks
who plan to move on to machine language
in the future.

Here's an example.  Here is how both
books describe memory location 124
(HOLDCH):

           Mapping the Atari

A character value is moved here before
the control and shift logic are
processed for it.

           Master Memory Map

A character that has been typed in from
the keyboard goes here so the OS
(operating system) can check out just
what kind of character it really is
(CTRL, SHIFT, etc.)

Now, if you were a beginning
programmer, which version would be
easier to understand?  It's like this
throughout the entire book!  Sources
for much of the information comes from
such famous books as DE RE Atari, DOS
Listing, Inside Atari DOS, Hardware
Manual (from Atari, Inc.), Mapping the
Atari, and OS Listing (also from
Atari).  The authors have taken the
best examples from all of these books,
and compiled them into an excellent
textbook for the beginning programmer.

And just like Mapping the Atari, this
book covers nearly all of the operating
systems, CIO routines, and much, much
more.  However, this book seems to be a
little out of date, and does not
include some of the memory locations
used with the XE series of computers.
It does cover some of the special
memory locations of the 1200XL if you
are one of the unfortunate people still
using this "white elephant".

I do not know if your local book store
can order this book.  I made a call to
the local B. Dalton book store and was
informed that none of their suppliers
had it.  I suggest you contact Best
Electronics or the book's publisher.
The cover price is $15.95 but might be
cheaper from Best.

         The Master Memory Map
    Craig Patchett and Robin Sherer
 Reston Publishing Co, Reston, Virginia

            Best Electronics
      2021 The Alameda, Suite 290
          San Jose, CA  95126
              408-243-6950

                    


      
      |ELECTRONIC MAILBOX AT HOME|
      
            
            |by Bob Fasoldt|
            

        Reprinted from the June
        Great Lakes Atari Digest


More and more people are buying
personal computers and a fair
percentage of them are purchasing
modems.  Electronic mail is not just a
thing of the future or just for the
wealthy.  You can set up your own
"electronic mailbox" and receive mail
while away from home or sleeping!  Let
me explain...

I live in Florida and the rest of my
family is scattered across the Eastern
United States.  Many of my family
members own personal computers and
modems so we send text files to each
other instead of letters...and the best
news is that it is often less expensive
than the mail service.  I have been
communicating with my family for about
two years in this fashion and find it
highly reliable and rewarding, plus it
is immediate!  When I get up in the
morning, the first thing I do is turn
on the monitor to see if any E-mail has
come in.  If so, I immediately save it
to floppy, even before I read it so
nothing can happen to it.

At first, we were using MPP 1000's
because their software supported
unattended downloading.  But soon I
grew tired of 300 baud and purchased
the Supra 1200AT which also supports
unattended downloading.  That software
however did not support the 512K
RAMdisk on my XE, so I began to look
for other software for this purpose.

In my opinion, Keith Ledbetter's
Express! is by far the best
telecommunications program available.
I began to wonder if this fabulous
program could possibly be set up to
autosave to buffer or to disk
unattended.  Nowhere in the 850
Express! docs was there any mention of
this so you can imagine my excitement
and happiness to discover that 850
Express! could indeed download and save
while no one was around!  And...wow, is
it easy to do!  Here is how:

==>Boot up your 850 Express! modem
program (I use version 3.0--I don't
know if earlier versions will support
this) and turn on your modem.  From the
main menu hit  (which forces
the program to think you're on line)
and then press OPTION (which saves
anything that comes in to buffer.  Set
up this way, as soon as a call comes
in, the modem will autoanswer and save
to buffer any incoming text.  To check
to see if any file has come in, simply 
turn on your monitor (I also hit the
 bar at this point to prompt the
computer out of the attract
mode--i.e. changing colors, etc.).  If
text is on the screen, hit  to
go the menu and save the buffer to
floppy.  This will clear the buffer so
now just view that file from the 
floppy or read your mail from a word
processor.

This has been tested on the Supra
1200AT, Avatex 1200 and Avatex 1200hc
and should work the same on most Hayes
compatible modems.  To test your modem
to see if it will indeed work in this
fashion, turn your computer and modem
off, turn your disk drive off and your
computer back on so only the READY
prompt of BASIC is showing.  Turn your
modem back on as if you were going to 
use it.  Now have someone call your
number.  If your modem answers the
phone without having a program to tell
it to do so, then it will work
perfectly as described.  If, however,
your phone rings and your modem does
not respond, you may have to command it
to auto answer in this way:

==>From the main 850 Express! menu,
choose ASCII (not ATASCII) translation.
Now hit  and with your modem
turned on and ready to receive data,
type ATAA.  Then hit .  (This
in all Hayes compatible modems commands
the modem to autoanswer.)  Now, hit


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