SJLOAD

About

SJLOAD is a C64/C64DTV software fastloader. Its main difference from normal fastloaders is that it only works with Jiffy-enabled drives and uses the JiffyDOS protocol. This makes it handy for people who have a Jiffy-enabled drive (also new hardware such as SD2IEC) but do not want to make the hardware changes necessary for exchanging the C64 kernal.

SJLOAD speed is a bit higher than normal Jiffy since SJLOAD uses the same protocol but a different implementation (it disables the VICII during load etc.). With an SD2IEC, SJLOAD is about 15% faster than a normal Jiffy kernal. Note that SJLOAD does not feature the command wedge and function key shortcuts known from a Jiffy kernal.

SJLOAD is loosely based on VDOS (1986) by Edward Carroll. However, the fast loading routines have been replaced completely by 1570 (contact).

Usage

• LOAD"!",8,1 - autostart SJLOAD
• LOAD"!*PROGRAM",8,1 - autostart SJLOAD, fastload PROGRAM
  • Since 1581 (compatible) drives do not stop filename matching at "*", use LOAD"!=PROGRAM",8,1 on these drives.
• LOAD"!",8:REM CHANGE DISK:RUN - save autostarting SJLOAD to (new) disk
• VERIFY - read floppy status - VERIFY"",9 reads status from drive 9
• VERIFY"command" - send floppy command
• VERIFY"$" - display directory - scroll to entry and press SHIFT +RUN/STOP  to load and run program

If a program crashes on RUN after loading it using SJLOAD, try RUN/STOP +RESTORE  (this disables SJLOAD) before RUNning it.

Status

SJLOAD is far from completed:

• Loading files bigger than 195 blocks makes the C64 crash
• Loading files below $0801 is not supported
• Only few tests have been made (with a C64DTV and an SD2IEC and in VICE)
• No IEC timing fixes for the C64DTV are done so the J1541/J1571+C64DTV combo does not work with SJLOAD (J1581 and SD2IEC do work). See here for a DTV solution.

I (1570) probably will not work on SJLOAD any more. The source is there, fix it! :-)

Download

• SJLOAD.ZIP including source for SJLOAD and VDOS. Also includes CRCCHECK, a testing program that repeatedly loads itself and checks its integrity.
• SJLOAD/SJLOAD.ASM - SJLOAD source in the wiki (just edit it if you have fixes at hand).

Links

• Petscii Forums: Thread "SJLOAD: Software fastloader for Jiffy drives"
• Retrohackers.org: Thread "SJLOAD: Software fastloader for Jiffy drives"
• Forum64.de: Thread "SJLOAD: Software-Schnelllader für Jiffy-Laufwerke"

• JiffySoft128 - a similar C-128 implementation
• SJLOAD-20 - a similar VIC-20 implementation