apple File Server Theory of Operation Apr85 free download

File name File_Server_Theory_of_Operation_Apr85.pdf

File Server Theory of Operation Michael Dhuey Ron Hochsprung 4 - 3 - 85 Table of 'Contents Introduction 2 1.0 Memory State Machine 4 1.1 Memory Map 7 1.2 CLOCKS PAL 11 1.3 DECODE1 PAL 12 1.4 DECODE2 PAL 12 1.5 RAMSM1 PAL 13 1.6 RAMSM2 PAL 13 1.7 IRQ PAL 26 2.0 Disk State Machine 27 2.1 Control Register 31 2.2 MISC PAL 32 2.3 DSTATE PAL 33 2.4 ENDCNT PAL 40 2.6 BCOUNT PAL 40 2.7 SHIFT PAL 42 2.8 SYNC1 PAL 42 2.9 SYNC2 PAL 42 2.10 ECCChip 45 2.11 Disk RAM Buffer 45 3.0 Disk Servo / Clock Interface 50 3.1 Versatile Interface Adapter (65C22) 50 3.2 Real Time Clock 56 3.3 SERIAL PAL 56 3.4 Soft Power 56 4.0 Serial Interface 58 4.1 Serial Communications Controller (8530) 58 4.2 MINI DIN-8 connectors 59 5.0 Small Computer Standard Interface (5380) 62 File Server - Theory of Operation (Preliminary ) April 3, 1985 Page 1 Introduction The File Server (FS) is designed to be a shared 20 (or 40) M byte file system for Macintosh. It contains one (or two) 20 Mbyte Winchester technology hard disks, 1 M byte of memory mapped RAM with 8 contexts, 64 K bytes of ROM, an 8 MHz 68000 CPU, two serial ports, and a SCSI compatible port. It is normally a shared resource on AppleTalk at 230.4 K baud. The Small Computer Standard System Interface (SCSI) is compatible with industry standard data storage devices such as Winchester disks, tape drives, and printers. It provides both expansion and media compatibility to devices not directly supported by Apple. The FS design can be divided into five logical components: the memory state machine, the disk state ma