On-Line #35 05 мая 1996

Железо

Mosaic - Connection DENDY'evskogo GPU to ZX Spectrum.

   Frankly I was pleased with yours, dear readers, support
my proposal to discuss some topics related to the expansion
Our Spectrum. Connect-ka and I to you. At this time, I will 
present their views on the connection DENDY'evskogo video 
processor. 


   Immediately say, that I would be awful would like to hear 
anything should on this subject from people who know the exact 
features video processors, its advantages and disadvantages, 
and not only from "Dilettantes in the codes." Since I do not 
have such information, this time limit, like the rest, the 
general impression of the prospects of merging so many 
different platforms and do not pretend to peer review.



   First, the same patient for the Spectrum issue - speed. I 
understand that the video processor will be faster, "throw 
away" sprites on the screen (by the way, I would like to know 
specifically for what speed), but the CPU it remains all the 
same - good old Z80. And the frequency is increased. Well if 
your goal is simply calculate the address of the desired sprite 
and display it, but so simple only in the demonstrations. By 
the way, is still unknown what sprites and how can display the 
processor, whether the He concluded by mask, etc. necessary 
techniques. Well, suppose that support, but as a vector and 
pixel graphics? Something I'm not very tempted by the prospect 
of drawing a point or line in buffer, and then just throw it in 
the form of a sprite (and even more so, as a group of sprites 
8x8 as DENDY). Yes, and I'm not sure, so that all possible - 
something I have not seen in DENDY'podobnyh consoles, anything 
resembling a vector or 3D graphics, all for some 
CARTOON'oobraznoe. Does this help anyone? I would say naeskolko 
words on the screen PROFI. Yes, the developers enlarged screen 
PROFI indeed, as if mildly, something nedodumali ... Increase 
the resolution, they did not nothing more, "ukruchivat" I'm 
talking about hardware scrolling and similar bells and whistles 
... But the "rumors" about his Ping, I think, greatly 
exaggerated. They are caused, probably, impressions from CP / 
M'ovskogo P / O. .. But to judge the speed screen for these 
programs - all the same, which to judge the standard screen, 
Spectrum, looking at the games in 1982, written in BASIC. 
Screen PROFI B / W mode contains 16 kb and 32 kb in a color 
that is 2.7 and 4.7 times respectively more than the standard 
screen. But since in the latest versions PROFI, when you turn 
on CP / M screen clock CPU frequency automatically increased to 
7 MHz and at This is still the possibility of including a turbo 
mode, which will You to 15 MHz (!), That is quadruple the speed 
of the Z-80, the practical ratio rate of change of the screen 
PROFI and the standard is, roughly speaking: 0.7 - if you do 
not touch attributes and 1.2 with all the colors. What kind of 
Latency question? When the appropriate approach to programming 
(such as applying speed "megademnye" algorithms) can create 
such a! When This 16 colors, 512h256 pixels to separate BRIGHT 
INK and PAPER and habitual SPECTRUM'ovskoe structure screen 
(about the genius who said so)! Not so bad ... 


   And about speed ... DIGITECS cites AY and says
that he hardly takes time CPU. This is somewhat
thousands of cycles "practically do not occupy? Not only takes 
time publication of individual sounds, but to get the music ... 
Sure that the withdrawal of one sprite 8x8 will happen quickly, 
and if need to display a series of ...? In addition, despite 
all the advantages AY to BEEPER'u, its quality has long been 
one not satisfied. Here and there were digital players, 
occupying all the time CPU, I'm sure that on the video 
processor will multicolor ... 


   Secondly, as far as I know, do not have a video deck
Output RGB (really a class DENDY it exactly), the processor 
immediately generates a composite video signal. What does this 
mean? Throw away your monitors and buy TVs with PAL color 
coding. I even I will not mention the cost ... But the picture 
quality will suffer. By the way, a connection more powerful 
video processor, with a large resolution also creates a similar 
problemma. Those relatively cheap monitors, mostly used by 
owners of SPECTRUM, simply unable to support the resolution 
more than 256h192 If the games it will not be so noticeable, 
then, for example, 80 characters per line 8x8 will be hard to 
discern, and hence again waste ...



  And finally, something small, but quite unpleasant for the 
true fan ZX - it will not be SPECTRUM! That is, in my

opinion, the most disgusting about this story, and that rested 
its case THE BIRD. Such modifications - it is not connecting 
peripheral devices such as modem or mouse (remember, DIGITECS, 
if connected to SPECTRUM'u hard drive, then get SPECTRUM with 
the hard drive), and a fundamental change in computer 
architecture (I certainly feel sorry for our poor professionals 
zheleznyachnikov suffering from unemployment, but their own 
money I feel sorry for more, even I do not know - why ...). 
Almost see a new version and how much it would glitches can 
only guess. And to call it have been as a type ZX-DENDY or 
ZX-NINTENDO. May enough for us all ZS-Scorpion, fanatical users 
and producers which is especially fond of pointing out, saying, 
"There SPECTRUM, and there SCORPION "? For those who do not 
know: ZS stands for" Zonov Sergei "(probably the author of the 
above options megalomania, once he puts himself on a par with 
Sir Sinclair). I do not know how anyone, but I prefer to work 
on SPECTRUM'e rather than ZONAL SERGEY'e or ZX-DENDY ... But it 
is not this. SCORPION AND PROFI and even forgotten by all ATM - 
it is still SPECTRUM, albeit with additional capabilities. But 
SPECCY + DENDY ... Well, think about yourself, what happens if 
we take the architecture of IBM, a video from the MAC? 


   Once again, connecting the video processor - no connection
periphery, then a simple soldering wires will not manage. AND
alteration of your computer would cost less than buying
new. Cheaper to create a new version. And even cheaper, once 
someone so like graphics DENDY, buy entot most DENDY (now the

cost a penny) and are not fooling people.


   As for our poor zhelezyachnikov forced
go to work in the stalls, in order to feed their families - 
suggest superproject. Judging by the results of a survey 
conducted by the newspaper LIME TREE, about 60% spektrumistov 
dream of a POWER MACINTOSH. Why not take a card from the Mac, 
sound card, HDD, CD and etc. to all this, the last central 
processing unit (that would be all others work in full power). 
Work there no end! If only firm APPLE you do not tear off his 
head for such a blatant theft ...



   With regard to the "everything is decided by the user: the 
user does not solve anything! The user will be welcome to all! 
All addresses a computer programmer!



   So here's what I think: the video processor is needed, but:


   1. inexpensive, so - collected on domestic details and
developed domestic zhelezyachnikami.


   2. legkopodklyuchaemy, so - designed specifically for
Spectrum, not to steal from another machine.


   3. allows not only the "sinklerovskie window" (even insulting
somehow ...), and the software and switching modes.


   4. having driven off to avoid the inevitable
glitches.


   I am sure many will disagree with me. E-mail, arguing ...
Can I change my opinion ... Let me remind you that more than 
just me interested in the specific technical characteristics 
and specific examples, rather than empty chatter-type "42 
Colors - 4 Plan ... Wow!.


                        Dmitry (OLDMAN)
                    MDM 496-8508; 12:00 / 21:00
                     ZXNet: 095:1641684 .. 4968508