calibrate_ppa

calibrate_ppa port unit

port
    Integer parallel port number (0-3): 0=LPT1 (0x378), 1=LPT2 (0x278), 2=LPT3 (0x278+1024), 3=other

unit
    Drive unit number (0-15) on the parallel port chain

The calibrate_ppa command is a legacy Linux utility for optimizing timing parameters of the ppa kernel driver, used with parallel port ATAPI devices like Iomega Zip and Ditto tape drives. It connects via Parallel Port Adapters (PPA) for low-cost SCSI-like access.

By probing the specified parallel port and drive, it runs automated tests measuring signal delays and factors such as interframe delay (if), strobe factor (sf), mode (mf), config (cf), and handshaking (hf). Results provide the best hexadecimal values and a ready-to-use insmod command line for loading the driver with tuned settings, improving data transfer reliability and speed.

This tool was crucial in the 1990s-2000s for stable operation on varying hardware, compensating for parallel port timing differences across chipsets (e.g., EPP, ECP). Today, it's obsolete due to absent parallel ports on modern PCs but remains in kernel sources for historical systems.

Legacy tool for obsolete parallel port hardware; requires paride and ppa kernel modules. No options/flags; positional args only. Run before loading driver. May fail on non-EPP/ECP ports or without drive attached. Not needed/supported on modern kernels/hardware.

Probing PPA port 0, unit 0
Best values: if=0x1e, sf=0x1e, mf=0x00, cf=0x00, hf=0x00
insmod ppa parport=0 if=30 sf=30 mf=0 cf=0 hf=0

Attach drive, unload modules if loaded (rmmod ppa), run calibration, then insmod with printed params. Check dmesg for drive detection.

Part of Linux paride subsystem since kernel 2.1.x (1997), peaked in 2.4 era for parallel-port storage boom. Included in kernel source tree (drivers/block/paride/calibrate_ppa.c) until ~2.6; now user-space binary in some distros or compilable from sources. Usage declined with USB/storage shift post-2005.

paride(4), ppa(4), insmod(8), modprobe(8), pdisk(1)