.if alone then start
.require "ttydefs.pub" source!file
.turn off "↑"
.tabs 5,10,15,20,25,30,35
.every heading (|DMT, Peek, PeekSum|,|February 12, 1979|,{page})
.once center
DMT, Peek, PeekSum
.skip 3
This documentation describes the operation of three related Alto Subsystems: ~DMT~, the Memory/Control Ram diagnostic; ~Peek~, the program to which DMT reports its findings; and ~PeekSum~, the program which summarizes the reports collected by Peek.

.sec |Creating a Peek Disk|

You should devote a separate disk to Peek.  Boot files can take up a lot of space and the Peek report file can get quite large over a long holiday weekend if your network has many hosts.  To avoid coming in on Monday and discovering your Peeker in Swat out of disk space, clean the disk out regularly.  Peek automatically keeps its network directory and boot files up-to-date, so building a new peek disk amounts to building an bare disk (OS, Exec, Ftp, Empress, perhaps Bravo), getting Peek and PeekSum and just running it: it does the rest.  I have written a canned procedure for building a Peek disk from scratch:

.begin indent 5,8
1) Boot an OS from the net and respond 'Yes' when it asks if you want the long installation dialog, and 'Yes' when it asks if you want to ERASE the disk.
2) When the erase procedure finishes, retrieve [Maxc]PeekDisk.cm and invoke it by typing to the Exec:
.begin verbatim
3) When the smoke clears, install your printer's name in the [HardCopy] section of user.cm and re-install Bravo.  If you aren't on the west coast, change the ZONE parameter (e.g to +5:00 if you are on the east coast).

.sec |History|

Chuck Thacker made DMT (early 1973) by combining many small diagnostics which he had developed to stress main memory using certain emulator instructions.  There were originally two versions: PMT (Printer Memory Test) which logged statistics on the Diablo printer; and DMT (Display Memory Test) which used the display.  Later (late 1973), an Ethernet driver was added to DMT, Bob Metcalfe wrote Peek, and Chuck wrote PeekSum.  At this point, development and maintenance of PMT stopped.  Still later (mid 1975), David Boggs added a Control Ram test to DMT, rewrote the Ethernet driver and took over maintenance.  Nate Tobol, who designed the Alto II memory system, wrote the Alto II memory test (mid 1976) which was merged into DMT.  David rewrote Peek and took over its maintenance.  Doug Clark extended PeekSum, and took over its maintenance (early 1977).

.sec |DMT|

DMT is written in the Alto BCPL-compatible variant of machine language and is distributed as a type-B boot file (see the BuildBoot documentation for more details).

When DMT is running, the Alto screen is black with a white cursor changing position once each time through the main loop.  For Alto I the cursor flips at random intervals; for Alto II the interval is about 1 second.  On Alto IIs with extended memory, the cursor contains a number between 0 and 3 indicating which bank it is currently testing.  DMT contains a TeleSwat server.  The key combination  causes DMT to stop and enter the debugger.

.ssec |Statistics|

If the 'S' key is depressed, DMT will display (and transmit on the Ethernet) the statistics it has accumulated.  The display looks something like this:

.begin verbatim

DMT of 25 Dec 78, Alto II XM 241. 456 blocks, testing 17341 to 176777
    0 bad main memory chips
    0 bad control memory chips

If there are errors, a line describing each type of error will be displayed, and then, if the errors can be resolved to a particular chip, the Card, Row and Column (for Alto I), or the Card and Chip number (for Alto II) will be displayed.  This display will stay up as long as the "S" key is depressed.  Periodically the statistics are automatically broadcast on the Ethernet and appear briefly on the screen.

.ssec |Booting in Response to Packets|

If DMT receives a request-for-connection (RFC) Pup and DP0 is ready, then it boots the Operating system and passes it a message of type eventRFC.  If the Executive section of user.cm contains an entry of the form:

.once center


then the executive will consume the event and execute the command line.
If DMT receives an EFTP data packet with sequence number 0 and DP0 is ready then it boots the OS and passes it a message of type eventEFTP.  This is included so that printers (which use the EFTP protocol) can drop into DMT when nobody is using them, and automatically wake up when someone wants to print.
If DMT receives a Kiss-of-Death Pup for socket 4 (miscellaneous services), then it EtherBoots the file whose ID is contained in the low 16 bits of the Pup ID.

.sec |Peek|

Peek opens several windows on the display.  The top window is for user commands.  There is currently only one: Quit.  The next window displays the release date of the program, a digital clock, the Pup internetwork address of the machine, and the number of free pages on the disk.  The next window is opened by the Peek Server and displays DMT reports as they arrive.

Peek loads special Ethernet microcode so that it can receive Peek reports directed to host 376b as well as conduct business as itself.  If it can't load the ram, it runs the Ether interface promiscuously and filter packets in software.  More diagnostic reports will be lost and booting may be slower, but things should still work.

Peek has a lot of options, and reads User.cm to find out what to do.  An example of the Peek slice of a User.cm file is given below.  In addition, it contains a host of network servers:

.ssec |Peek Server|

If there is a line of the form "Peek " in User.cm, Peek will start up a Peeking process which will listen for raw Ether packets of type PeekReport and write them on .  The filename should be 'Peek.reports' since PeekSum, described below, assumes this (I was just feeling general the day I wrote that code).

.ssec |Event Report Server|

Peek implements the Pup Event Report protocol.  For each line of the form "ERP  " in User.cm, Peek will instantiate an event report process which will listen on socket  and write event reports on .  The default address which the OS uses is Maxc, so I don't expect many people will use this, however it might be helpful for an Alto site that isn't connected to the Parc Internet.

.ssec |Pup Echo Server|

Peek contains a Pup Echo server running continuously in the background.  PupTest and GateControl contain Echo users with which you can poke it.

.ssec |Raw Ether Echo Server|

Peek also contains a raw Ethernet Echo server.  This is the echo protocol used by EDP and NEDP, the diagnostic programs for the Alto and Nova Ethernet interfaces.

.ssec |Boot Server|

Peek implements the protocols necessary to be an Alto boot file server.  For each line of the form "Boot  " in User.cm, Peek will send  when it receives a Mayday packet requesting bootfile .  If the file isn't on the disk, or if Peek discovers a neighboring Boot server with a later version, your Peek will aquire it.  The more boot files you tell Peek to keep, the less space there is for Peek reports.

.ssec |Name Server|

PeekSum consults the file 'Pup-Network.Directory' to get the owner and location of Altos.  Peek contains a name lookup server and in addition to answering lookup requests, keeps its copy of the directory current.

.ssec |Time Server|

Peek also has a time server.  Alto time is based on Greenwich Mean Time, and
local users must know their local time zone and the beginning and ending days of Daylight Savings Time to convert to local time.  Time servers are the source of this information, so it is important that the time parameters in User.cm be correct.  "Zone +8:00" means that the peek disk is 8 hours west of Greenwich -- in the USA Pacific Time zone.  The standard User.cm contains this, so you must edit it if you live elsewhere.  The Daylight Savings Time parameters are set by the line "DST 121,305", and only change when Congress messes with time.  Keep an eye on your local CongressPerson.

.ssec |User.cm Example|

Below is an example of the Peek part of a User.cm file.  In this example DMT statistics go to the file 'Peek.reports', Event reports addressed to socket 30 (swat error reports) go to the file 'Swat.ERP', and some maintenance-type boot files are available for diagnosing Altos.  Notice that all characters between a semicolon and a carriage return are considered to be comments and ignored by Peek (this is not true for all programs that use User.cm).

.begin verbatim

 ...executive stuff...

; Syntax:
; Boot  
; ERP  
; Peek 
; Correction  (decimal) [positive makes clock go faster]
; DST   (decimal)
; Probe  (decimal)
; Zone : (decimal, plus is west of Greenwich)

Peek Peek.reports	; for PeekSum.run

ERP 30 Swat.erp		; Swat Error reports

Zone +8:00		; USA Pacific Time Zone
DST 121,305		; DST begins on day 121 and ends on day 305

Boot 0 DMT.boot
Boot 5 CRTTest.Boot
Boot 6 MadTest.Boot
Boot 10 NetExec.boot
Boot 11 PupTest.boot
Boot 12 EtherWatch.Boot
Boot 13 KeyTest.boot
Boot 15 DiEx.Boot
Boot 17 EDP.Boot
Boot 20 BFSTest.Boot

 ...bravo stuff...

Peek writes the contents of User.cm into the Command window as it reads through the file.  If the file has bad syntax, Peek will call Swat with a description of its complaint (e.g. "[ReadNumber] - number contains illegal characters" if it is expecting a number and reads something other than 0-7).  Typing -U will restore the user display.  The last item in the Command window is what Peek is having trouble with.

The source code for most of the servers in Peek is borrowed from the gateway program, and so there are some more specialized commands which you can ignore and which default to reasonable actions.  I mention there here for completeness.  "Correction +20" means the Alto's clock looses 20 seconds per day, and the time server should correct by gaining 1 second at 20 equally spaced times during a day.  "Probe 1" means attempt to locate newer versions of boot files and the network directory once an hour.

.sec |PeekSum|

PeekSum reads the file "Peek.Reports" (the output of Peek) and constructs a summary of the errors reported by DMT (see above) for each Alto.  PeekSum writes on the file 'PeekSummary.Tx' a tabulation of the error reports, together with the owner's name and the machine's location, retrieved (if possible) from the file "Pup-Network.Directory", which is maintained by Peek, as described above.

As Peek is started and stopped, it writes short messages to this effect on Peek.Reports; these messages are reproduced at the beginning of PeekSummary.Tx.  The number of the local network is also written.  If Peek.Reports contains multiple reports from a single Alto (which is usually the case), PeekSum will record the largest number of errors of each type, over all such reports.

PeekSum will complain and then gracefully stop execution if the files Peek.Reports or PeekSummary.Tx are unopenable for some reason.  If Pup-Network.Directory is unopenable or absent, the ouput file PeekSummary.Tx will not include names and locations of Altos, but will contain error reports grouped by Alto host number.

To run PeekSum, just type:


and the program will go about its business.  When it has finished, PeekSummary.Tx should be printed on your local printer.