date : 7-19-91 The following references are ones I use: 1) the Users Guide for the Floppy Disk Controler_Plus (A Western Digital Clone), 2) the 1989 National Semiconductor Mass Storage Hand Book (referencing the Floppy Disk Controller_Plus2 or the NS DP8473 Floppy Diskette Controller), 3) the NEC 1981 Catalog for Microcomputers or the NEC æPD765, 4) the NEC 1987 MicroComputer Products Databook; Microprocessors, peripherals, & DSP products vol 2 of 2; the NEC æPD7265,NEC æPD72065 and NEC æPD72066 5) the IBM Technical Reference Manual for the PC, 6) the IBM Technical Reference; Personal Computer AT 7) the Western Digital DataBook; 1991 Devices (referencing the Floppy Disk Controller or the WD37C65C), 8) the 1983 INTEL Microprocessor and Peripheral Handbook (referencing the Single/Doule Density Floppy Disk Controller or the 8272A), 9) the 1985 INTEL Microsystems Components Handbook, Volume II 10) the 1987 INTEL 80286 and 80287 Programer's Reference Manual 11) the 1984 ROCKWELL DataBook;Semiconductor Products Division the R6765 12) the IBM PC Troubleshooting & Repair by Robert C. Brenner 13) the IBM PC Advanced Troubleshooting & Repair by Robert C. Brenner 14) the IBM Personal Computer Troubleshooting & Repair; for the IBM PC, PC/XT and PC/AT by Robert C. Brenner 15) 8088 Assembler Language Programming: The IBM PC by Willen & Krantz 16) IBM ROM BIOS: Programmer's Quick Reference Series by Ray Duncan floppy disk controller chips I know of ====================================== NEC 765A/7265/72065/72066 Intel 8272A National Semiconductor DP8473 Western Digital WD37C65A/B/C Rockwell R6756 Hitachi HD68435 " HD68a435 -- Ibm 3740 format only Signetics 8x330 Texas Instruments 990/303a ?? (not sure) ACER ??? Hyndai ??? Toshiba ???