AltIOMaxc Operations168. ALTIOAltIO serves as an Alto Input-Output package which does all the input-output for Maxc except forthe disks. Specifically it does input-output for the Alto monitor, the Diablo printer, the Ethernetand the IMP (ARPA Network).8.1. Calling AltIOAltIO may be called either from Midas or directly from the Alto Executive. In Midas, selecting"AltIO" with the mouse causes a menu of AltIO subcommands to appear. Selecting "Do-It" causesAltIO to be started with no options selected; in this case, AltIO performs no initialization butsimply resumes the microprocessor at its current location. If other subcommands are selected before"Do-It", they modify the initial actions of AltIO in various ways.When AltIO is called directly from the Alto Executive, the same options may be specified byswitches. The general form of the AltIO command line is:AltIO/switches parameter/switch parameter/switch ...The switches immediately following "AltIO" correspond to Midas "AltIO" menu items in thefollowing way:SwitchMenu ItemDescription/BBoot-MExecBoot Micro-Exec into Maxc memory and start it./HDont-GoLeave Maxc halted rather than resuming it./PProtectEnter "protected" mode in AltIO. This means that AltIO willallow only those commands that examine (but do not write into)memory and that do not change machine state./RReset-MemoryReset the memory system./SStart-TenexStart Tenex, first booting Micro-Exec from disk as for /B and thenexecuting an automatic "Go" command.The optional additional parameters may be specified only in the Executive command line; there isno way to invoke them from Midas.filename/LLoad a PDP-10 "save"-format file into Maxc memory (default extension .SAV).Used for loading PDP-10 diagnostics when Micro-Exec won't work.n/UUse disk unit n rather than unit 0 in Boot-MExec and Start-Tenex commands,where 0 corresponds to unit A and 7 to H.)fq;pi '_rX Zfs` X Y V S_rX OsJ N#D LXF J:* HB EQ Q C9@X6 <F : 7fr] 3s] X. 0]* -]#+E.){, & ] X "] = $ Z^ !  +S?  =)` =W<Maxc OperationsAltIO178.2. AltIO CommandsWhen AltIO is running, the Alto monitor is divided by black lines into three windows. If Tenex isrunning, the top window continuously displays the addresses and contents of five interesting Maxcmain memory variables. The middle window belongs to a command processor for controlling AltIOitself. The bottom window implements the Maxc controlling terminal used by Tenex and by stand-alone programs such as Micro-Exec and PDP-10 diagnostics.Keyboard input is directed to whichever window currently contains the blinking cursor. The middleand bottom unmarked keys on the right side of the keyboard may be used to direct input to themiddle and bottom windows respectively. Keyboard input is automatically switched to the bottomwindow when Maxc is started by commands such as "Boot" or "Go", and to the middle windowwhen Maxc stops for any reason.The AltIO command processor has two heralds, a number sign (#) which indicates that onlycommands that examine memory are legal, and a colon (:) which indicates all commands are legal.AltIO commands consist of a single letter or other special character, optionally preceded by anumeric argument. The argument is an octal number of up to 40 bits, depending on the command.While typing an argument, one may use the editing characters control-A, control-W, and Delete toerase, respectively, a single character, a word, or the entire command.Many AltIO commands request confirmation with "[confirm]". The confirming character is aReturn or period. Most of AltIO's commands are intentionally the same as in NVIO; the ones forwhich this is true are marked with a superscript "1".n/1Change the current Maxc memory location to n; and print out the contents of thatlocation in the form:aa bbbbbb ccccccwhere:aa (0 to 17) is the last 4 bits (i.e., the "tag" bits) of the 40-bit Maxc memory word,it is not printed out if zero;andbbbbbb and cccccc are the left and right half 18 bits of the PDP-10 (Maxc) word./Print out the current location.n1Put the 40-bit number n into the current location. The first 4 bits input are the last 4bits of the memory. Thus one can think of Maxc as a 36-bit machine (like the PDP-10), right adjusted in a 40-bit field, rather than a 36-bit machine left adjusted in a 40-bit word as is actually the case.This command is only legal after a command which prints out a Maxc memorylocation.1(lf means linefeed). Change the current location to the current location plus 1, andprint out the (new) current location. fpiAuqFp _r [s'; YK XH VDK Ty9 Qb O=%8 MrF K? I Fk9 D-2 A.:$ ?d"< =<$ ;G 8]: 6+5 45 1U1t1UsP/S-3X*S(=S&$aS" F X &t&s?[MD!T =  t sI  M% >]AltIOMaxc Operations18n1Equivalent to n, , .^1Change the current location to the current location minus 1, and print out the(new) current location.n^1Equivalent to n, , .1Change the current location to the location pointed to by the current location. Printout its contents.B1Boot Micro-Exec from Save Area 1 of physical disk unit A.nB1Boot Micro-Exec from Save Area 1 of physical disk unit n (0=A, 1=B, etc.) Theparameter n is remembered for subsequent "B" commands without arguments.DToggle on or off a switch causing typeout on the Maxc controlling terminal (thebottom display window) to be copied to the Diablo printer. This switch is normallyoff, but turning it on is useful when debugging Tenex or doing memory maintenance.EPrint out the current state of Maxc's PDP-10 emulator. This includes the programcounter and all the accumulators. This command may be issued only when Maxc isstopped.nG1Go to Maxc location n. Precisely: stop the Maxc microprocessor (cleanly if possible),then tell it to begin executing PDP-10 instructions at Maxc main memory location n.GGo to the starting address of the currently loaded Maxc program, which is pointed toby Maxc memory location 7.H1Halt Maxc (cleanly if possible).LPrompt for a filename (default extension .SAV), then interpret that file as a PDP-10"save"-format (not "ssave") file and load it into Maxc memory. The program'sstarting address is stored in location 7 so that a "Go" command without argumentswill start the program. The file is expected to be in the 36-bit binary format definedby FTP. Retrieving a PDP-10 "save"-format file using the FTP program will causesuch a file to be created.M1Halt Maxc (cleanly if possible) and return control to Midas. Midas is resumed inwhatever state it was in when control was last transferred to AltIO from Midas. Thisis true even if AltIO has been exited and other Alto programs run in the meantime.nM1Go to Microprocessor location n. (If you use this command, you had better knowwhat you are doing.)P1Protect NVIO. The herald becomes a number sign (#); only those commands thatexamine memory (and other state varibles) are legal.)fq;pi  ^s_9t^sX/ [:[t[:sFYo UVtUsX/ RStRs6P MOMtLMOsX8 IJjtIIs0HH D)&BJA > =Q;G: 67t6;)6s!444 1UI / ,,t+,sX (M&,!%A#G0'!}H @t@s* 6-U@u:4 9t9sOU9Hn ts @24 [+(Y)YY)YY)YY)YY) UXX RERtQREs?PzJN@L IsJtIIssX2 FFtEFsB BQ ?''=S ?;< ;A<, TIMESROMAN  TIMESROMAN  TIMESROMAN  TIMESROMAN  TIMESROMAN <j/ڒMaxcOps8.BravoRWeaverSeptember 24, 1981 7:00 PM