Think #44 18 марта 2000

Программирование

Hackers - On the programming VG93.

             HACKERS ... ...


 for computer users Spectrum
 From: Slava Grigorjew 2:5030 / 946.36
 Subject: # F6 # F7


 NS> How to format, read and write

     sector, with the numbers # F6, # F7 in TR-DOSe?

Read and write the most ordinary way.
Format slyly. When a controller asks for formatting the sector 
number, nyzhno podsynyt emy # F7. In sharp ones he writes 2 
bytes of control symmy, kotoryyu decides based on the past 2 
bytes (the number track number side). Poetomy order

to get him to write instead of
control symmy what we need (namely,
sector number [any, including the # F6, # F7, and
etc.] and dliny sector) must be chosen
correctly, according to his (VG93) algoritmy
counting control symmy track number and
number of parties. But, back to the formatting. After these 
manipulations on the track has finally arrived are played: 
nom.dorozhki; nom.storony; nom.sektora the length of the sector 
formed VG'shkoy team # F7.


Further, according to formaty MFM need to write 2 bytes of 
control symmy title sector. But since the SH has finally 
arrived recorded something similar, then these must first 
calculate pychkami and podsynyt has finally arrived in the 
finished form. For all this nyzhen like you has finally arrived

guessed ishodnyak to count counter.
symmy algorithm SH.

P.S. Presented method is not yniversalen,
as have, as a rule, rather than by track number and record a 
kakyyu biliberdy. Secondly, if the records of these

bytes or iskystvennoy control symmy
nyzhno bydet record any prohibited nibyd type byte of the same 
# F7, then bydet BIG meat.