ACNews #21 24 июля 2003

Thoughts - the number of discs 5'25 gradually decreases, there is nowhere to buy them.

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                        Here he is, RULEZZZ!
(C) KSA-7G


   Unfortunately, the number of discs 5'25 gradually decreases, 
there is nowhere to buy them. Older drives slowly pouring. 
Serious alternative to becoming ... TAPE, which has repeatedly 
proven its reliability of data storage!


   You can get the old cassette's 80-ies, and successfully read 
it, even trite, unless you have a good TARE interface. 
Interestingly, the readability of even weak, mint record is 
better than chipped drive. Probably because you can drive it

as much as necessary and make the correction signal tone. On 
the disc is unrealistic, because drive issue is a digital 
signal. 

   In general, triggered an old principle - the simpler - more 
reliable, and of course, the fact that the density on the tape 
below. But it seems I have missed something ... Of course, this 
drives 3'5. Alas, their density is even higher, and they are 
less reliable disks 5'25, although very convenient. 
Fortunately, the lot of them, and, according to Dennis, they 
are well work.


   But I do not drive 3'5, although I think in the future to 
deliver. You might think about using video, and in view of 
progress - and memory cards. All of this is real, but requires 
appropriate devices. 

   In the meantime, use Disk 5'25, often beaten sectors, format 
through the FUT, but as we know, the error may eventually 
manifest themselves on specially-formatted disk. That 
dopolzovalsya ... 

   Drew a number of schemes, and sometimes corrected. First 
drive habitually re-read the data, but once the issue was 
aggressively standard message. REPEAT has not helped.


   I began to copy the screen to another drive, long and hard, 
but all my patience was not enough, and I had Ignor'it sector. 
At issue were four pictures. One was completely normal, the 
error was issued when loading its attributes, but as all my 
circuits, it was black and white, so even with Ignor'om I 
received a normal screen (probably was damaged by the checksum 
itself). The other picture was damaged BITPLANE. One - The 
entire upper third and middle part. I have regained almost all 
of the middle part - sorry, not the whole picture. The other was

damaged portion of the upper and middle third of the screen. 
Because of the schemes I have almost completely restore it. And 
the last image was damaged part of the middle and lower thirds 
- I restored it completely! On the last picture was damaged 
small text, and on some lines left - two rows of the screen, but

considering your spelling, and remembering the meaning, I 
managed to fix it. 

   Bottom line: people, you can not even imagine that we have 
... Yes, thing that is haunted by many, makes writing tricky 
procedure, and confusing tables ... This is our 6,912-byte 
screen, with its by-8-mistrochnoy structure! Actually it: HW 
Interleave DATA. For example - what is done with the music just 
before recording to a CD, make special chips! We are going to 
the screen, using simple logic, DAR is a little Speccy! Because 
of this I was able to recover pictures. If the lines were 
straight, I would be irretrievably lost Part kartinok.Vot it - 
RULEZZ! Here - a vivid example of data protection and recovery, 
taking into account the redundancy. After all, whether he 
narisovany me the standard written text - I'd completely lost 
it. On the screen he redundancy of 200% (2 lines (100%) - length

text, and 4 lines (200%) - in excess).

   Noted one feature (which previously did not know). Like, when
download code from BASIC and Ignore broken sectors, bad sectors
not loaded in the specified area, and there is old information. 
Anyway, when the load battered image over the old one, on it 
were visible part of the old pictures. 


   I'm sure there were such cases in the history of the Speccy. 
Nice to know such elementary data protection. I decided (and 
once do it) to create an archive of their schemes on tape, but 
how do you keep? Compressed? Or simple displays? I really can 
not solve it, because the packed screen devoid of redundancy 
(for the most part). Perhaps we can establish two cassettes. A 
60-minute will write zapakovanye screens, and a 90-minute prime.


March 19, 2003 Year period KSA-7G