Maxc OperationsIntroduction11. INTRODUCTIONThis document describes many of the commonly used procedures for Maxc operation, as well as anumber of uncommon procedures used during system debugging and maintenance. Also includedare the complete operating instructions for several pieces of software written at PARC and uniqueto Maxc; these include Midas, AltIO, DMPLD, and Micro-Exec."Maxc Operations" is intended primarily as a reference document for system personnel. However,in the absence of system personnel, any user should be able to restart Maxc from a Tenex crashusing the procedure outlined in Section 2.Conventions used in this document: In examples in which user typein is intermixed with machinetypeout, the user typein is underlined. , , , and are used to stand for the carriagereturn, line feed, space, and escape keys.1.1 Overview of the Maxc SystemFrom a user terminal, Maxc looks like a PDP-10 running the Tenex operating system. However,this is mostly an illusion. Maxc is really a PARC-constructed microprocessor which emulates thecomplete user-mode PDP-10 instruction set, as well as some privileged instructions, equivalents forthe BBN pager operations, and an additional instruction set for Interlisp. The Tenex system hasbeen considerably modified to account for the many differences between Maxc and a PDP-10,particularly in the area of input/output.The system consists of the following major components:A.The Maxc microprocessor itself. Besides performing PDP-10 emulation, Maxc also directlycontrols the disks.B.A 384K-word by 48-bit MOS memory system, with hardware built in for correcting single-biterrors in any word and detecting (though not correcting) double errors.C.Up to eight disk drives, each connected to its own controller inside Maxc.D.The Maxc system I/O controller is an Alto, which provides Maxc access to the Alto's ownmonitor, a Diablo printer and the Ethernet and the IMP interface supporting Maxc's connection tothe ARPA Network.The Alto also performs a number of other important functions relating to system initialization anddebugging. It has direct access to Maxc's main memory (through a separate memory port) andindirect access to all of the internal microprocessor registers and memories. It can load microcodeinto Maxc's writable control store, and can command Maxc to start and stop execution, single step,and perform a number of other useful operations.The Maxc system operates under the control of a large complex of support software, most of whichis described in this document. These programs are described here, in approximately the order theywould be used if one were to bring up the system from scratch. fpi>q Gp#^rX [:s,1 Yo> W': U< RhU P6( N* Ka2- II?rI * G* Br ?As\ =vO ;:) 9C 8K 6K) 2X6 /h29 - *+2-, (`G $2XJ !}2L K  u"@ J U E K0 R  V D> =\IntroductionMaxc Operations2When first booted, Maxc's Alto runs under the control of the standard Alto operating system andhas a number of the usual Alto subsystems on its disk.Assuming the necessary files have been loaded onto the Alto disk, the next program to be run isMidas. Midas is the loader and debugger for Maxc microprograms. It has a large number ofcommands for examining and changing microprocessor registers and memories and for starting,stopping, and single-stepping the microprocessor. Most of its capabilities are used only duringdebugging; in the normal course of events, it is used only to load the PDP-10 microcode intoMaxc, and it then passes control to AltIO.AltIO is the program in control of the Alto while Tenex is running on Maxc, and contains all thenecessary I/O drivers for communicating between Maxc and the peripherals connected to the Alto.AltIO also has a command decoder, by means of which the operator may examine and changememory, start and stop the Maxc microprocessor, and perform a number of other operations.One important AltIO operation is to boot into Maxc main memory and start a PDP-10 programcalled Micro-Exec. Micro-Exec has commands for performing a large variety of stand-alone Maxcoperations, such as setting up the disk configuration, copying disk packs, and (most important)loading Tenex from disk and starting it.Most of the rest of this document is devoted to explaining the above operations in much moredetail.1.2.A Word on Terminals and ConsolesThe Alto's controlling terminal is, of course, the monitor labelled "Maxc Alto". When the Alto isrunning the control program AltIO, the display is split into two main windows. The upper windowis the command window for AltIO itself, whereas the lower window is the emulated Maxccontrolling terminal. Keyboard input is directed to the window in which the blinking cursorappears; this may be changed by striking the middle or bottom unmarked key on the right side ofthe keyboard. The Maxc log is a Diablo printer.Ordinarily the screen is black; it will turn on when you type something on the keyboard.Note: Subsequent sections discuss commands that you may have to type to various systems. If youscrew up, the following table gives standard conventions for deleting the previous character orprevious command typed:Delete CharDelete CommandExecutiveBS or AcDELMidasBS or AcDELAltIOBS or AcDELThe TI-700 terminals in the room are connected to the Alto DLS, which is not directly a part of theMaxc system.)fq ;pi _sJ ]K6 Y-2 XZ VD< Ty` R+2 P* Mr T K4+ I? HY DB BM A O ?A( ;!; : 51r2X 1sb /M .*< ,_1+ *N (0 %XX !tsT  R Q ? +i ms!-m! -!-  Xc U  >Y TIMESROMAN  TIMESROMAN  TIMESROMAN  TIMESROMAN  TIMESROMAN j/aMaxcOps1.BravoRWeaverOctober 21, 1981 10:20 AM