How can I build a modem-to-modem connection?
I have succeeded in connection between a PC and Mac for transmitting downloaded files, using direct modem to modem connection (this has advantages over a serial link, for example it is much easier to set up and use). This connection can of course be used for any two computers.
The secret of fast, reliable modem/modem linking is a "line simulator".
Without one, some modems will work together directly by themselves; others may connect with difficulty, and only run at the slowest connect speed, or not connect at all.
A simple line simulator consists of a 9 to 12 volt battery or power supply, a resistor and a capacitor and two phone jacks. This is adapted from info at http://www.hut.fi/Misc/Electronics/docs/old/telephone_intercom.html
Get two phone jacks and a 380 ohm, 1/2 W resistor. Connect the components to make the circuit below:
Green 380 ohm 1/2W + 12V - Red
To Modem To modem
Place a .47 microFarad audio grade filter cap (I used a polyster cap) from the "green" end of the resistor connection shown above to the "red" end of the power supply connection. The value of the resistor should be adjusted to allow about 25 milliamps, or not more than about 30 mills max, to flow when both ends of the circuit are connected and "off hook".
I got the above resistor value by connecting an old phone to one end, clipping red to green at the other to complete the circuit using only one telephone device, and measuring current by connecting a DMM (digital multimeter) in series with the power supply on the meter's milliamp setting. If you don't have a meter, you can start with 1000 ("1K") ohms for 24 volts, or 500 for 12 volts or 380 ohms for 9 volts and if it works leave it at that. If you use a cheap "wall wart" (i.e., plug in power supply) you may need to add an electolytic capacitor of about 1000 to 3000 microfarads across the power supply connection (match the plus and minus of the cap with plus and minus of the power supply, or the cap will overheat and blow up) to clean up the dc output.
If your connection works reliably without this extra filtering, you don't need it.
Run the terminal programs on each computer, and type ATX3&C0 (that's "C Zero"); this will make sure that the modem doesn't look for dial tones,etc. Make your communication settings the same on each (usually you will use "Xmodem" at 9600, N, 8, 1 on a Plus for file transfers). Then to connect, type ATD and enter on one computer first, then ATA and enter on the other. They will connect; now you can activate "send file" on one and then "receive file" on the other.
If you are connecting a PC to a Mac and have only Hyper Terminal available on the PC, see http://www.helpdesk.umd.edu/faqs/comm/dial/atdirect.html
How can I speed up the SCSI port?
The slow SCSI speed of the Plus is a problem with the early SCSI implementaion used on the Plus. Most upgrades do little to help this, they mostly help the cpu speed. Helping the cpu run faster, though, often painfully points out the slow Plus SCSI. System 7 points out the slow SCSI speed too.
The Mercury/MicroMac Performer 030 upgrade will only help SCSI speed by about 10%. The Brainstorm 16mhz 68000 upgrade helps about the best I've ever found, increasing the SCSI speed by about 40%. I love my Plus, I live with the dead slow SCSI and serial ports.
Ach! What is a disk image?
A virtual disk. It is, essentially, a file on the hard drive that can be mounted to the desktop, which, then, looks, acts, and modifiable, like a NORMAL disk.
When mounting a disk image, it uses some RAM, though small, to accomplish this task. When you access the virtual disk, it points back to the original disk image file. However, you can COMPLETELY mount the ENTIRE disk image into RAM, if you have enough. If you have a disk image containing an enourmous number of files (small), it can be accessed faster via RAM (in nanoseconds) than it can via hard drive (in milliseconds).
In the Wintel world, there is such a thing, though it is not commonplace. (No, I'm not talking about NT and its virtual Mac volume.) I know people
who use it for backing up [data] CDs (and the sort) to the hard drive. (Don't ask me why.)
You can mount disk images (.img) with ShrinkWrap (shareware), StuffIt Expander 4.5 (integrated ShrinkWrap features), Apple Disk Copy, Disk Dup+ (shareware), and other similar utilities that you can download from the Internet.
How can I create a boot disk?
You either create a custom one or use the disk called, "Disk Tools". To create a custom boot disk, duplicate the System and Finder files from the
System Folder to a different location (e.g. desktop or new folder). If System 7.x, open the System copy, and remove all the fonts (if System 7), sounds, and keyboard layouts, putting them in the Trash. If System 6.x or lower, remove all fonts and cdevs with Font/DA Mover. You should be able
to fit these two files, as well as a copy of Disk First Aid and another
If these two files are still too big for a 1.4MB floppy (or 800K disk, if you have only an 800K drive), "shred" non-essential resources (e.g. color) with FloppySystem Trimmer. However, problems of systems being too big were
only introduced in System 7.5. (I'm not talking about doing things with
400K disks or the sort.)
If you own a copy of Norton Utilities, you can have it make a boot floppy with Norton Disk Doctor on it. Some of these boot disk may not be able to
access the desktop, depending on how much space is on the floppy disk and
what Mac you're using.
You can also create a boot disk with custom software on it, though more risky for the integrity of the software, if you don't know what you're doing. In System 6 or lower, you could just put a copy of the System file and an application, named Finder, then with THAT application ("Finder") highlighted, select Set Startup from the Special menu, and click OK. In System 7.x, you will need to modify the creator/type to FNDR/MACS,
respectively, with ResEdit, GetMoreInfo, or similar resource-modifying program, as well as changing the name to "Finder". (You have to make sure
that the boot blocks of the floppy disks are GOOD. Otherwise, the Mac will spit the disk out.)
This procedure, essentially, tricks the Mac in thinking that your modified application is the actual Finder. (Note: The Finder is just another application. You can quit it, using special software.)
I used to always use my PowerMac 6100 (running 7.1.2, now running 7.5.5) to create/modify/add things to System 6 boot disks.
The only issue is that if you put it into a System 7 (or later) Mac, make sure that you don't let it rebuild the desktop on the disk. That's because
System 6 used a big file called, "Desktop". System 7 eliminates that file
and puts "Desktop DB" and "Desktop DF" in its place by rebuilding the
disk's desktop. Even then, the disk should boot the Plus to the desktop,
and say something that it can't modify the desktop on the disk, and when
you dismiss the dialog box, the Mac restarts.
There is no problem with creating System 6 boot disks on System 7 Macs.
You just need to make sure that your System 7 Mac is running in tip-top
condition. Both Systems use the Hierarhieal File System (HFS), unlike
pre-System 6 systems, which use Macintosh Filing System (MFS). Even then,
I was able to create/modify/add things to pre-System 6 boot disks on my
The only incompatibility is with OS 8/8.1.
What about a Zip drive connected to my Plus?
These are my experiences with a Zip Drive and a Plus-
1) A zip drive makes a very stable HD for a Plus, I know people who have been using them as a bootable HD for YEARS (yes, YEARS) with only occasional
problems that Norton has fixed (BTW, I've had to use Norton on my new G3 HD
Once, so I don't see this as a zip problem)
2) You need to use an Iomega Driver older than version 5.x. Otherwise you
get a sad Mac when booting. You also can NOT allow your zip disk to be
loaded in a machine with a 5.x driver, 'cause part of the driver will update
itself, and give a sad Mac when booting with a zip disc in the drive.
3) The best thing to do, in my opinion, is get a small (cheap) SCSI HD for
your plus, put SSW on it, including your Iomega driver. I use a 30MB myself.
Boot off of the HD with no zip disc in the zip drive, insert zip disc after
booting. The zip disk can now be used as a non-boot volume, which also makes
backing up files easier onto a second zip disc. (hint: only keep SSW on your
boot HD- this leaves plenty of room for transferring backups from zip to HD
to back-up zip, less disk swapping)
This will work regardless of whether or not your zip driver has been
polluted with a 5.x system. Note- if your driver has been polluted (like the
one on my Plus) you MUST boot with no zip disk in the zip drive. That's why
I say it's best to boot from a small HD, because you don't have to worry
about what computer your Zip Disk is used in.
Note- this driver update thing was a VERY bad feature on Iomega's part! I
know of one case where an individual with a Performa had the 4.2 driver and
zip tools. he used his zip disc in a Mac with a 5.1 driver, went home and
used it in his Performa. The next time he booted, he put his zip disc in the
Performa before booting, had no problems- until he tried to use his zip
tools! he got a nasty message saying he couldn't use his tools 'cause they
were too old for his driver! As it turns out, he could only use his tools if
he boots with no zip disc in the drive. Because Iomega thought they were so
smart, he had to upgrade his Iomega stuff to consistently use his drive the
way had been using it no problem before.
and Salupo family says:
..you can run a Zip as a Boot drive on a Plus. You need a Zip disk that
has been formatted with Iomega tools v4.2. Hook the Zip to the Plus, set
the termination "on", and put a disk in with a valid System folder.
Should boot just fine. I do it with my Plus. My machine has no other
SCSI devices and 4Mb of RAM.
If you use any other version of Iomega driver the Plus will not boot from
the disk. You will only get the blinking "?" icon. v4.2 was the first
version of Tools to ship with a Zip Drive.
Also, Iomega tools will not fit on an 800k floppy with System 6.0.8. So
you have to format the Zip disk on another Mac.
Does System 7.5 run on a Plus?
I have installed System 7.5.5 on a 4MB Plus with no problem at all.
Where can I get the driver for my Zip?
http://surf.to/macdrivers can probably help you out.
Help! My Plus has intermittent video!
This weekend I was messing around with an Apple monitor that had unstable video. I discovered that the problem came and went as I flexed its circuit board. I couldn't see any bad solder joints or loose connections, so I thought "What the heck, I'll just resolder every joint even if it looks good." Ten minutes later I had a monitor with perfect, stable video.
Emboldened, I did the same thing to two Mac Pluses that had thermally-related intermittent video. Bingo, now they work, too, and they only took around 3 minutes each.
Moral: don't think, don't research, don't inspect, don't agonize, just slobber solder everywhere and hope for the best!
Does my Plus work with ISDN?
My IIci (20 MB, Sys 7.5.5, OT 1.3, FreePPP 2.6.2) is connected with a ISDN terminal adapter.
FreePPP allows 115200 bps on the serial port, so I can use the whole 64000 bps bandwith of a ISDN channel.
BTW I also tested a Plus (4 MB, Sys 7.1, MacTCP 2.0.6, MacPPP 2.0.1) with
ISDN. - It just works :-)
What MIDI software for my Plus?
A great starting point for MIDI software is http://www.aitech.ac.jp/~ckelly/mmuig.html
There is lots of commercial MIDI software available for old macs; I think the mac was just a more popular platform for professional musicians back in the late-80s. I can't get the shareware sequencer, MIDIGraphy, to work on
Most of the commercial software has demo versions available. See:
And make sure you get the demo for MicroLOGIC. It does sequencing AND
notation, and it works on a plus!
Of course, the problem with the 68000-based macs is that they contain rather primitive synthesizers... 4 voices, max, as I recall. (Concertware+ did the best it could :) But If you have a cheap keyboard with MIDI connectors, you can play better music than a Power Mac. You will need a MIDI interface. I bought a MiniMacman http://www.midiman.net/MAC.HTM at Guitar Center http://www.guitarcenter.com/ (A must-see if you happen to be in Hollywood, CA)
Opcode Systems used to sell a package called MusicShop, which included a MIDI interface and software for under $100. But, once again, I was blown away by MicroLOGIC from emagic.
How can I build a 800K System 7.0 boot disk?
A procedure for building a System 7.0 boot disk that fits on an 800K disks at http://www.best.com/~tenebrus/steve/
How can I open the case of my Plus?
http://www.edprint.demon.co.uk/se/index.html should be able to help crack any Compact Mac.
How can I transfer some file from my PC to my Plus?
YES! Aha! I may not know how to do much more but I would be happy to share
What it came down to was a serial connection to my PC and download the files
to the floppies. What you NEED is a floppy with a terminal program on it.
I use ZTerm 0.9 since it handles ZModem and can fit on a bootable flopppy.
This part is a chicken-and-egg thing so find someone with it on disk already.
Go get a Mac modem cable that will allow you to plug your serial port into a DB-25 modem, then either buy or wire up a null modem. You're done for hardware. Next, run a terminal program on the desktop and connect to it with ZTerm. I haven't been able to go past 19200 but I also have a 50-100 foot null modem! (never checked, but it's seriously out of spec). Test it by typing "asdf" on each keyboard (the standard test phrase) and hopefully it should show up on the other screen. Next, transfer the files!
I could (so far) only transfer MacBinary2 files (.bin extension) and have them become usable on the Mac, hqx may not work (or if it does I don't know how).
What about Unix on my Mac?
Some fun to have unix on an se........
I dont know how to use, not a Unix guru, but its complete etc...and the idea of a real multitasking thing with system 6.....;-)
This morning I got a mail, explaing some of the mac specific commands. The Prentice-Hall book isnt on the net, but here is a snippet, maybe somebody
eject -- eject a diskette from a drive
hdclose -- close hard disk partition
hdopen -- set correspondence of a HD partition to a MacIntosh file
maccreate -- create an empty MacIntosh file
macfile -- list, read, and write MacIntosh volumes
macread -- read a MacIntosh file
macwrite -- write a MacIntosh file
rmaker -- a simple resource compiler
settype -- set type and/or creator of a Mac file
Dont ask me for the details, ask around at comp.os.minix, thats where Linux
The URL for minix is ftp.cs.vu.nl/pub/minix etc...look for Macintosh.
There are some manuals at, see the other snippet
I should have mentioned in an earlier message that the entire Minix 1.5
reference manual is available at minix1.hampshire.edu in the
/pub/refman.1.5 directory. Also a set of man pages for Minix 1.5 is
available in /pub/minix.1.5/man.
Its not macspecific, but.......
The hqx files from Amsterdam is around 5 MB, took me one hour with a 14400
GV, around the same time for decoding, so if you can sacrify two hours..
And then, I had to log in. Password ??? Voila
the login name is root and the password is Geheim (it's case
sensitive) hope that's what you need
also, the extra users on there are
ast , Wachtwoold
you can edit the passwrods for all of them while logged on as root or
as the user
MacMinix is just a programm, there is MacBoot, you doubleclick on it etcpp.
No difficult HD manipulations needed. Read the files in etc to get some
kind of a clue, whats going on. First thing I did was to write a .kermcr
file for ast, set line /dev/tty3 etc., next thing will be some other file
in /etc that I can log into the SE from the outside.