Articles - COMPUTER EQUIPMENT COMPUTER "KAY-256"

Section 2
COMPUTER EQUIPMENT
COMPUTER "KAY-256"

(c) Nemo,
St. Petersburg,
those 159-55-69

   The computer we offer to your attention
KAY-256 belongs to the Spectrum family
and developed by Nemo (St. Petersburg)
burg), which has experience in their development and production
production.
   Why Spectrum?
   Many of those who read these lines
are faced with the problem of choosing their brand
first computer. Talk about what
"Spectrum" is dead, "Spectrum" is obsolete and
etc.  It's been going on for several years now. However, me-
her, manufacturers still produce
dat, and users purchase "outdated-
"shiy" cars.  The point is that for now
simply by purchasing a more advanced type
computer to achieve new quality is not
perhaps. Requires painstaking work
mastering a new type of technology: - up to half-
years of personal time and effort, not
talking about material costs. This
associated with changes in the informal circle
communication and search for new ways of "production"
information, software, hardware, technical
escort, etc.
   Atari and Com computer users
modore, who have fantastic technology
technical characteristics, unable
realize their potential due to information
onny "vacuum". The established domestic
market of household computers and its information
structure is oriented primarily
on "Spectrum" and practically no support
other industrialmodels. Volumes
available proprietary software
cookies on Spectrum far exceed
the total volume of software of all other radio amateurs
computers (“Specialist”, “Ori-
he", "BKOO10", "RK-86") combined.
   A few words should be said about IBM
PC.  For entertainment purposes, buy one
an expensive “toy” hardly makes sense.
SEGA or Dandy are more suitable here. How
practice shows that home IBM is usually
duplicates the computer installed on the
bot and is used primarily in com-
commercial and production purposes. In
in many ways (text preparation and
etc.) the cheaper "Spectrum" is capable
replace IBM PC. Talking about prospects
"Spectrum", don't forget about this
concept as user inertia
market, which in St. Petersburg is estimated
a period of six months to a year. And this
for computers of the same type with
full software compatibility between
itself and almost complete within
"Spectrum" - families. Even if
triumphant march of Commodores (as
this happened, for example, in the Baltic
republics) it can be assumed that before the growth
they will reach the Siysk outback no earlier than
in two or three years.

          Development ideology

   In the process of working on the design of the op-
The following approaches have been identified that allow
offer it as a mass household
of your computer.
   1."Spectrum" compatible machine with
open architecture. Decisive factor
choice is the amount of available software. Liu-
broken hardware expansion of the main board
is devalued by the uniqueness of its software. Poe-
Therefore, only "Spect-
rum"-architecture, and specific tasks
specific user groups can re-
interact with peripheral devices,
the ease of connection of which is given special attention to
tactful attention. The concept of "systemic ka-
"nal" was defined in the form of a system bus
three-dimensional slot layout. Possible
the periphery is divided into two classes: a) fast
paradise - installed on the system bus in
in the form of slots inside the case; b) slow
- connects via a loop as a separate one
structural volume outside the housing (che-
res bidirectional parallel port).
This made it possible to avoid buffering
tires and make it more predictable and
simple.
   2. Quite a large amount of RAM (256
K) is immediately placed on the main board, so
how to increase the amount of RAM in the process
operation is associated with a number of technical
difficulties.
   3. Use of existing standards
on connectors and signal levels. Inter-
face peripherals compatible
with CENTRONICS, made according to IBM standard
PC (Canon DB-25S connector) [1, p.20].
The prototype of the system bus was the system
dark connector of a branded computer. Pa-
parameters of signals that control the TV(monitor), basically correspond
TV standard.
   4. Ensuring good reproduction
bridge, manufacturability and availability
product reliability at minimum cost
property.  Cost is minimized for
computer as a whole, and not just for the OS
new board, as was done most
your developers earlier. Payment is calculated
for installation in the case of the Corvette PC.
The printed circuit wiring was done by Vla-
Dimir Korovichev (KVA).
   5. Initially, the task was not set to
obtaining 100% software compatibility with
branded "ZX-Spectrum".  It was decided not
install the FFH port, since there are no cons-
it does not perform productive functions (for
with the exception of the test for own presence-
chie). In addition, enough is used
rough decoding of addresses.

Literature

1. Printing devices for personal
Computer: Directory. Ed. I.M. Vitenberg.
- M. Radio and communication, 1992. 208 p.