Alex Wulms <[EMAIL PROTECTED]> writes:
>>> - Fastcopy Transfer (I/O transfer) -> 22'6 Kb/s (!!!!!)
The absolute maximum speed of any 720kB floppy disk, even on a 250MHz
Pentium Pro, is calculated like this:
Sectors_Per_Track * Bytes_Per_Sector * Rotations_Per_Second
All drives rotate 300rpm = 5 per second.
A 720kB disk has 9 sectors per track. (1.44MB = 18 sectors so it's 2 times
faster than 720kB)
9 * 512 * 5 = 23040 bytes per second.
As Alex writes then the head stepping also takes time. If the head cannot
be
stepped fast enough from track to track then the drive might loose 1
rotation per step because the head have passed sector 1 on the new track.
If you replace the diskdrive in the Turbo R with a new PC drive then you
can
improve the step-delay of the FDC in the Turbo R. This value is being set
only once by the diskbios, so we can set it ourselves after boot.
When the original Turbo R diskdrive steps only 1 track at a time then the
long step-delay isn't needed, but when moving the head many tracks then
it's
needed.
Here is a basic program which set's the Step_delay in the Turbo R FDC.
*** Use is on your own risk!!! ***
When stepping only small steps at a time works fine with the original Turbo
R drive, but larger steps often requires repositioning and that means that
it's actually going to get slower than with the normal step_delay!
I copied a random disk with the DOS COPY command to harddisk.
Normal step_delay : 147 s
Faster step_delay : 170 s
So as you can see then it doesn't pay off when you use the original drive.
Exchanging the drive with a new and faster one works much better but there
is a little problem with the dust protection lid :( You have to remove the
front of PC drives to make it fit in the Turbo R.
Modify the POKE line to change the step-delay. #DF is the normal Turbo R
value, #EF is a faster steptime, #FF is the fastest, #0F is the slowest.
The upper 4 bits are the Step_Delay time, the lower 4 bits are the Head
Unload_Delay time. The address after that defines the Head_Load_Delay
(lower
4 bits)
A value of #F is the shortest time, #0 the longest time!
Regards,
10 'Set the STEP_DELAY on the Turbo R
20 '(C) Henrik Gilvad 1994
30 'USE ON YOUR OWN RISK!!! (Use with new PC diskdrives works fine)
40 '
50 CLEAR200,&HD000
60 A=&HD000
70 READA$:IFA$<>"$"THENPOKEA,VAL("&H"+A$):A=A+1:GOTO70
80 DEFUSR=&HD000
90 POKE&HD003,&HEF '0F=Slowest, DF=Normal, EF=Faster, FF=Fastest
100 A=USR(0)
110 DATA 18,03,03,DF,03,26,40,3E,8B,CD,24,00,CD,18,D0,3A
120 DATA C1,FC,26,40,CD,24,00,C9,21,D0,07,3A,F4,7F,E6,10
130 DATA 28,06,2B,7C,B5,20,F4,C9,21,02,D0,06,03,3A,F4,7F
140 DATA E6,C0,FE,80,20,F7,7E,32,F5,7F,23,10,F0,C9,$
Henrik Gilvad <[EMAIL PROTECTED]>
