SPEED MANAGEMENT COMMANDS FOR LUNIX
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by Ilker Ficicilar - February 1997
   filker@newton.physics.metu.edu.tr
   e068214@orca.cc.metu.edu.tr



    Here, four commands for speed selection in LUnix is introduced. Two of 
them has not much effect on C64 but C128 in C64 mode. They have the 
disadvantage of closing the VIC screen. So you better use these commands
only on the server machine, or use them with 'vdctty' 80-column VDC screen
driver.

    The explanations of the commands follows:


fast128 : This command installs a patch to the LUnix kernel's 'lock' and
         'unlock' routines, makes itself resident in the memory, switches
         to 2MHz mode, and switches off the VIC screen. The patch monitors 
         the lock requests, if a process wants to use IEC bus, patch switches
         to 1MHz mode. When the process calls unlock routine, the patch 
         turns on the 2MHz mode again.
          If you have a C128 this command speeds your machine by 133%, that
         is 2.33 times faster. The 'mips' command shows 0.852 mips, meaning
         that a process can execute 852000 CPU op-codes in a second. If you
         have a C64 use 'fast' command instead. Because 'fast128' eats two
         pages of memory and gives only 17% of increase for stock C64s.

slow128 : Simply uninstalls the fast128 patch and turns into 1MHz mode with
         the VIC screen is on. It also frees the two pages, allocated by
         'fast128'.

fast    : It switches off the VIC screen, so without bad raster lines, you
         gain about 17% of speed increase. The mips command gives 426000
         op-codes per second. This means that you can execute 61000 more
         CPU op-codes in a second (not so bad!). I suggest you to use this
         if you have C128 and 'fast128' conflicts with your net-activity.

slow    : This command switches on the VIC screen. So, takes 17% of speed
         back. If you issue this command while the 'fast12' is active, you
         will see a garbaging! VIC screen. This effect causes from the fact
         that VIC chip can only run at 1MHz, and at 2MHz it fetches garbage
         from the system bus. Issueing 'fast' again closes this ugly screen.


   Thats all. They are not tested much. So, if you have problems with them
please inform me.


Ilker

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