Deja Vu #08 31 мая 1999

Будущее Спектрума

Topic - Provision # 2. Perspective.

AY-Track: SECTOR / SMG / CTL / C.DION / TITANIC!
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(C) Andrey Ovsyannikov
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         RESERVES # 2. PERSPECTIVE



         - What are the similarities between the female legs

           and the Ostankino TV tower?

         - The higher podnmaeshsya, the more

           breathtaking.



                        People, people ...



   First of all I want to vyrazt gratitude to the authors of 
the journal for publication both articles and royalties ("Oh, 
bother - Copy) magazine, as well as Michael and

Dmitry Ivanisheva ever assist me and advice in writing these
articles.

   Compilation of number seven
literally shocked - to date digest
pores and can not catch my breath. Shock - it's on our own.


   Continuing the affected me in a previous
magazine theme (RESERVES ZX-SPECTRUM)
I want to say that the vast majority
implementations of the platform built in
accordance with the principle of "all_in_one". In
This is one of the main drawbacks, probably, of all currently 
existing models. 

   Lack of this is that when you try to
connect to the car for something or improve it
characteristics and capabilities somewhere, right
there is a problem soldering iron and a scalpel.
Even if there is a system connector (a
in Leningrad-2, Magika, Byte, etc., your
the pros, its a Scorpio, the lack thereof in
Pentagon ATM - Turbo ... and this list
You can go on and on ... ).

   In other "ochumeltsev on top of one scheme
You can see another of the bells and whistles, and various 
"improvements" that is fundamentally changing the work scheme. 
A different look, think, and saith then the great and mighty: - 
"Let it all go in ...!"; and if enthusiasm for computers has 
not yet cooled down, the platform change is clearly not far 
off, but statistics show that it will be probably not "AMIGA" 
... 

   For myself I say that to grasp at these two
devaysa I also do not like: we need a very
good reasons for this "upgrade". On the other hand, the desire 
to adapt the work my car (a car) "under the company" at all 
costs, can play horseradish passage, unless the code: we again

come to begin, that is, to a closed (not the right word - 
zaderevenevshey) architecture and as a consequence: "Spectrum 
is dead!" 

   And now, after so blues inflections
The first two parts (as it should be in chorus), proceed to the 
third. A look at the machine to conquer the world - on the PC. 
You can obkakivat it from all sides, but genius architecture - 
the bus - it's worth noting separately. Neither Intel, nor the 
Gates Foundation, namely the bus, only slightly changing, make 
the PC so popular, because it all the flexibility and power of 
PC. 

   Changes everything: CPU, memory, clock speeds, but as was 
ISA, well worth it. Appeared AGP, PCI, changing the bit,

faded MCA, EISA, and the main
slot only added extra.

   Well, with the subdominant to the tonic. Technology 
"all_in_one" doomed. Survival can only be flexible architecture 
that implements a good enough emulation ZX-SPECTRUM.

It is emulation, since the Spectrum - a
what makes the Amstrad. Everything else is just
emulators, and often very distant from the prototype. In this 
case, you may want to give up some things inherent in it 
ZX-SPECTRUM: stopping the processor when running with the 
display, unresponsive to display second line of memory, and a 
few public. On I think the best solution for emulation is a 
compromise of ATM-Turbo and profiles containing basically the 
Pentagon. Incidentally, in ATM-Turbo is present divided by the 
output memory interface and a number of original circuit 
design, but For me this machine is a sad

example of how to screw up a different
kind of twists, maybe a new platform.

   The desire to drive in the motherboard as possible
more - a dead end. You can not grasp neobyatnoe.
It is more appropriate principle of necessity
and adequacy.

   Using two (or three, or more) lines of memory will 
dramatically reduce the demands on her speed, if the memory 
operates in alternating lines, or sliding mode CAS'a. (The RAS 
is applied to all lines simultaneously, and CAS-turns). Perhaps 
we should pay attention to the mode of RAS after CAS. 

   At the core architecture will undoubtedly be
lie bus (very suitable candidate for
this role - ZX-BUS (SPECTRUM-EXPERT 1, 2)).
Possible extensions should bring up an extra slot. Memory must 
contain at least two lines and separated out

on the data bus. This will provide
new modes for the same display. If you organize the lines are 
not the banks, but say, on an "even-odd" that provide the same 
access as the display and processor, as well as a 7 megahertz 
less inhibition (or may not be his). CAS and RAS should serve 
simultaneously on both lines, separated by only WE signals and 
gates of the reading processor memory. This solution is much 
cheaper and easier, than the use of buffer memory and 
sverhbystrodeystvuyushego shadow screen, as in Sprinters. Very 
interesting experience with Z80 as a video processor in the 
ZX-NEXT. Unfortunately, no information about this car I have, 
so to speak specifically this can not.


   As a decoder suitable for my
opinion, is the use of RAM-type 155
RU2, the initial installation of which is carried out with the 
full discharge of a separate boot ROM (it's ATM Turbo). To set 
vremyanok can use firmware machines, where instead of using RAM 
ROM, downloadable from the same starting ROM (MP-machines are 
used in older drives 5305, 5311, 5313, and in some controllers 
TR-DOS as a PLL; in the pros it is organized sync). This can be 
expensive and complicated, but much more affordable than using 
alterovskih bisin. It is worth thinking about and access to all

programmable devices in the process.

   Clock frequency is to choose 7 megahertz, realizing 
switching TurboNormal skip taktov.Skolko memory? The more the 
better. Shrieks the fact that such soft no, I will answer: - 
"There would be vodka, but we will always find a reason." 

   Now, just a little on the display. As a reference, a first 
approximation, consider implement it in such a machine, as 
Locke. " This Spectrum provides a 64 color

each point, but its details are buried
in the depths of Amstrad.



   Well, we lost the entire chorus and came back to the 
beginning, that is, to the epigraph. Having considered this 
concept of the basic architecture seen that the prospect of 
really good and zelo bad. But it will be even cooler if we did 
unload the processor more or less intellectual periphery. And 
climb even higher. And even higher than the leg. And our 
euphoria legitimately change to ecstasy. 
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