136 lines
6.2 KiB
Plaintext
136 lines
6.2 KiB
Plaintext
MiniSport Laptop Hacker - Vol 19. Jan 1994
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To discourage pecuniary interests, Copyright (c) 1993 Brian Mork
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>>> ADMIN
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Remember, you can get copies on disk of any software or text file I re-
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fer to (including the MLHacker series) by sending me a disk and SASE.
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I'll put a variety of other MLHacker related goodies on there, too.
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Alternately, you may make a direct call to the data number listed below.
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In this case, use the FILES command, and L)og into the \public\computer
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directory.
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MLHacker is starting to show up on some Internet servers. Ask around or
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you can offer to upload it for me to your nearest host.
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>>> PARALLEL PORT POTENTIAL
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The August 1993 (Issue #37) issue of Circuit Cellar INK has a six page
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article describing how to turn the PC parallel port into a powerful TTL
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input/output port, even if it's inherently only an output port (prior to
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the proliferation of PS/2 compatible bidirectional parallel ports). The
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circuit uses only five chips: 2x 74LS374, 2x 74LS244, and 1x 74LS138. I
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will eventually build one and report on some fun things to do with it,
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but in the meantime, I thought I'd give a pointer to the article to oth-
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ers in the crowd who could use this capability now.
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>>> 2ND MEGABYTE ADDITIONS
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Thanks to Griff, Troy, and Jeff. Each has experimented around with the
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empty sockets in ZL-1s that hold a second megabyte of memory in ZL-2s.
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Bottom line is that you can add a standard IBM PC SIPP (1Mx9) or a Mac-
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Intosh type (1Mx8) memory package. If you have SIMMs, you'll have to
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add some pins, and in some cases, trim the circuit board card to fit in
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side the Minisport case. In all cases, you'll have to bend the package
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of memory over sideways after soldering it in. Yea! Anybody have some
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spare memory they'd like to sell me? The "old fashioned" slow memory
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would work fine in this computer.
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>>> PACKET CONVENIENCE UTILITY
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I bet most of us use our Minisports for packet at one time or another.
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Here's a utility I recently wrote to fix an annoying problem. The com-
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puter and the TNC are doing what they're suppose to, but that's not what
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I wanted! The limited storage of the Minisport's RAM disk prompted me
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to do this one in assembly language. You may have seen it on the nets
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as a stand-alone message. As a special addition to MLHacker readers,
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the source code is included prior to the text of the other message.
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; PK232DMP, initiated Jan 94, BjM (Opus-OVH)
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;
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XOR AH,AH
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MOV AL,1 ; COMx -- put 1,2,3, or 4 here
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PUSH AX
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ADD AL,030 ; Convert COM number into ASCII
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MOV [FILL],AL ; Create output message
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POP AX
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SUB AL,1
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SHL AL,1
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MOV BX,AX ; COM address offset into BX
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MOV AL,040
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MOV ES,AX ; BIOS Data Area Segment
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MOV AX,ES:[BX]; Snag COM base from DOS table of addresses
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ADD AL,4 ; Generate BASE+ModemControlRegister
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MOV DX,AX ; put it into DX
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IN AL,DX ; Get existing Modem Control Register
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OR AL,3 ; Set DTR and RTS true, and..
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OUT DX,AL ; rewrite to hardware
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MOV AH,09 ; Select DOS "String->Std Output" function
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MOV DX,STRING ; DS set by MSDOS prior to entry
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INT 021
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MOV AH,04C ; MSDOS Program Termination
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INT 021
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STRING: DB 'DTR and RTS on COM'
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FILL: DB ' set true.$'
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Whenever I exited my TNC communication program and did other things with
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the computer, my PK232 continued to monitor the airwaves and eventually
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the text buffer filled up. At this point, it would accept no new con-
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nects to its built-in mailbox, would stop monitoring traffic, and would
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log no new callsigns. I wrote this short program to set DTR and RTS
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true on the PC compatible COM port connected to my PK232. Now, I exe-
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cute the communication program (I use TPK) from within a batch file and
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execute this file from the same batch file after the main program ends.
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The PK232 thinks the comm program is still monitoring and it continues
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to send stuff the computer, keeping its internal buffer empty.
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----- cut here -----
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e 0100
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32 E4 B0 01 50 04 30 A2 3D 01 58 2C 01 D0 E0 8B
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e 0110
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D8 B0 40 8E C0 26 8B 07 04 04 8B D0 EC 0C 03 EE
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e 0120
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B4 09 BA 2B 01 CD 21 B4 4C CD 21 44 54 52 20 61
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e 0130
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6E 64 20 52 54 53 20 6F 6E 20 43 4F 4D 20 20 73
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e 0140
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65 74 20 74 72 75 65 2E 24
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r cx
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0049
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n pk232dmp.com
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w
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q
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----- cut here -----
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Cut out the 15 lines between the "cut here" lines and put them all by
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themselves into a file called INPUT.DBG. Use the MSDOS DEBUG program to
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generate an executable .COM file using the command:
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C:> DEBUG <INPUT.DBG
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A bunch of stuff will scroll across the screen. When it finishes, there
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will be a 73 byte file called pk232dmp.com in the default directory.
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Type "pk232dmp" on the command line to execute this program.
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Another COM port may be selected by changing the fourth byte (currently
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01) to another COM number, up to 04. For example, if you want to access
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COM3, you would change ...E4 B0 01... to ...E4 B0 03... and then run
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debug to generate another copy of pk232dmp.com. No provision is made to
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accept a command line input of COM port number in order to keep the pro-
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gram very small. Perhaps you could make several copies called
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dump1.com, dump2.com, etc.
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>>> CROSSFLOW
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Troy says he has an EPROM burner that he can make copies of ROMs with.
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Rather than blithely throwing out his e-mail address, let me know if he
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could help you. I'll pass your name on and let him get hold of you. At
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least one person has experienced sector errors on disk C: as a result of
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the built-in ROM going bad. It's a standard chip, so copying someone
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else's and replacing yours should offer no technical trouble. Is any-
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body out there brave enough to hack out the format of the ROM disk and
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tell me how to replace some of the MSDOS 3.0 distribution files with my
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personal files? Now that would be sweet! Power up the Minisport and
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have my own programs in ROM. Leaves extra room on the ROM disk, too.
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Maybe my next project... after the laser radar. See 'ya next month!
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Please provide feedback! * Direct data 1-509-244-9260
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* AX.25 KA9SNF@wb7nnf.#spokn.wa.usa
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* Internet bmork@opus-ovh.spk.wa.us
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73, Brian * 6006-B Eaker, Fairchild, WA 99011
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