Commodore RF512C - Direct - Block Programming

34
DIRECT - BlO CK PROGRAMMING
Ot he r then file opera ti on, Jser can directly mainpulate the disk
itself wi th very less involute in prog r amm ing.The way is using the
drive RAM as buffer for data processing.
Demo for block read, write and its paint er.
10 INPUT " DI SK ID ':X$
20 CLO SE 1:0 PEN 1, 8,15
30 CL OS E 2:0 PEN 2,8,2, "#"
40 PRINT.!' 1, " UI :2 0";18:0
50 PRINT'" 1, "B-P";2;162
60 GET.!' 2.1S : GET#2,DS : IDS = IS+DS
70 PRIN T" OLD 10 I S"; IO $
80 PRINT'" 1, "B -P ";2;162
90 PRINT'" 2,X$
100 PRINT# 1, "U 2: 2 0 "; 18;0
110 CL OSE 2:CL OS E 1
LIN E 10 : Input new disk 10 code
LINE 20: Open command channel
LINE 30: Open buffer channel
or one can put a speci fi c buffer number affer " #"
LINE 40: Using U1 to substi tute block-read on track 18 sector 0
LINE 50: Set block-pointer to 162 (i.e. ID code location)
LINE 60: Get 10
LINE 70: Display the old 10
LIN E 80: Again, set pointer to 162
LINE 90: Input new 10 into buffer
LINE 100 : Using U2 to substitute blOCk-write on track18 sector 0
LINE 110: Close file
Oemo for bl oc k -ass ign fun ction
10 CL OS E 1:0 PEN 1, 8,15
15 PRINT# 1, "I C6"
20 PRINT# 1, "B -F:'0;18;1
30 PRINT'" 1, "B-A "0;18;1
40 G OS UB 100
50 PR I NT.!' 1, "B-A"0;18;1
60 GOS UB 100
70 ENO
: RE M free the block
:R EM allocate such block
:R EM OK message
: REM al locate it again
: REM no block now