for "Atari System V", as the manual calls it, the operating system's kernel identifies itself as "UniSoft UNIX (R) System V Release 4.0. Technical specifications All TTs are made up of both custom and commercial chips: Custom chips TT Shifter "TT Video shift register chip" — Enables bitmap graphics. Features a 64-bit wide bus with interleaved access to ("dual purpose") system memory and on-chip buffers for high bandwidths. Contiguous 32 KB memory for ST modes, 154 KB for TT modes. TT GLU "Generalized Logic Unit" — Control logic for the system used to connect the STs chips. Not part of the data path, but needed to bridge chips with each other. Used in TT and MEGA STE. DMA "Direct Memory Access" — Three independent channels, one for floppy and hard drive data transfers, one for the SCSI port and one for 85C30 SCC network port. Direct access to ("dual purpose") system memory in the ST. 2 chips used. MCU "Memory Control Unit" — For system RAM. Support chips MC6850P ACIA "Asynchronous Common Interface Adapter" — Enables the ST to directly communicate with MIDI devices and keyboard (2 chips used). 31.25 kilobaud for MIDI, 7812.5 bit/s for keyboard. MC68901 MFP "Multi Function Peripheral" — Used as an interrupt controller, timers and RS232C ports (2 chips used). NCR 5380 "SCSI Controller" — 8-bit asynchronous transfers up to 4 MB/s. WD-1772-PH "Western Digital Floppy Disk Controller" — Floppy controller chip. Zilog 85C30 SCC "Zilog Serial Communications Controller" — Two high-speed SDLC serial ports. YM2149F PSG "Programmable Sound Generator" — Provides 3-voice sound synthesis, also used for floppy signalling and printer port. HD6301V1 "Hitachi keyboard processor" — Used for keyboard scanning and mouse/joystick ports. MC146818A "Motorola Real Time Clock" CPU: Motorola 68030 @ 32 MHz (system bus @ 16 MHz) FPU: Motorola 68882 @ 32 MHz RAM: System RAM ("dual purpose") 2 MB ST RAM expandable to 10 MB TT RAM ("single purpose") expandable to 256 MB TT RAM on daughter board using either 30-pin or 72-pin SIMMs Sound: Yamaha YM2149 + Stereo DMA 8-bit PCM, same as in the STe Drive: 1.44 MB (later version) or 720 KB (first TT version) 3½" floppy disk drive Ports: MIDI In/Out 3 x RS-232 Serial LAN RS-422 Printer VGA Monitor (analog RGB and Mono) Extra Disk drive port ACSI and SCSI port VMEbus inside case Cartridge (128 KB) Keyboard (detachable) Joystick and Mouse ports (on keyboard)