Networking Your System 6 Mac

At this point in our series of posts about System 6, we have explored why you might be interested in System 6, what sorts of Macintosh units you might want to purchase to support that interest, and what minimum “starter kit” of software you might need to get you started in this new environment. Now it is time to load your System 6 machine up with the software you really need to make productive use out of the system.

There are two “usual” ways of doing this, networking the new machine with other Macs you may have, so that you can simply load new software across the network, and attaching mass storage devices such as an Iomega Zip drive or a CD-ROM and transferring the software in that way. This post explores the first of these two topics, networking your System 6 Macintosh. The last and final post in this series on System 6 will explore second option, adding mass storage.

The word “networking” deserves a little exploration of its own, in order to set the context for this post. There are two major forms of networking that could we could pursue: Apple’s own AppleTalk and the ubiquitous (today) Internet.

AppleTalk is an Apple proprietary set of protocols that allows two or more Macintoshes, along with other compatible devices, to communicate with each other. AppleTalk can run over either a simple serial connection between two or more units (LocalTalk) or it can run over Ethernet (EtherTalk), and thus address any compatible machines on your local home network.

In addition to AppleTalk, most people will want to get their new System 6 machine onto the Internet and the Web, and so this is an objective as well. We take this later objective with a grain of salt however, remembering that while a System 6 machine can make excellent use of many Internet resources, there is very little, if anything, that a System 6 machine can do on the web.

A practical consequence however of wanting both AppleTalk and Internet connectivity is that we will focus on AppleTalk over Ethernet… EtherTalk. Thus, this is the context in which we pursue “networking” in this post.

For the most part, we will need to start from scratch. Out of the box, your new System 6 installation will typically not come with AppleTalk, any form of TCP/IP stack (needed for the Internet) or even any form of Ethernet drivers.

To achieve our objective to AppleTalk over Ethernet, and the ability to access the Internet/web, we need to install both networking hardware and networking software.

Let’s start with the hardware. In order to accomplish networking, your machine needs to have network interface hardware at its disposal. Your machine may come with networking hardware built in, or you may need to install a NuBus network interface card (NIC) of your choice. Apple provided a range of Nubus NIC cards at the time, and similar cards were available from other vendors as well. I recommend the Apple NIC cards of the period to start with, simply because the drivers are largely available as part of the NSI 1.4.5 package.

This is what I did with my Macintosh IIsi. I purchased (on eBay) a Mac IIsi-specific PDS-to-Nubus extender, and an Apple NuBus NIC card. I physically installed this hardware before I began my networking software upgrade, and as a result the drivers for the new NIC went in as a seamless part of the NSI software install.

That’s the hardware – onto the software. You will need to install the following software, in order:

1/ Apple Network Software 1.4.5 (AppleTalk – will run over LocalTalk to start with)

2/ Ethernet drivers for the NIC hardware that is either built into, or you have installed on, your System 6 machine. As mentioned above, remember that drivers for many Apple NIC Cards are included in NSI 1.4.5.

3/ MacTCP 2.0.6, providing you with a System 6 compatible TCP/IP (Internet) stack.

As you approach your networking software installation, your new System 6 machine provides no networking support at all. Both the Network and the TCP/IP control panels are not present, and the Chooser control panel in all likelihood contains only one or more printer selections, and no AppleTalk selection, looking rather like this:

Chooser, No AppleTalk Selection

Like many things Macintosh however, transforming this into what you want is almost painfully easy.

In my case, I used my Power Macintosh 7300 to burn a copy of NSI 1.4.5 (the last version of Network Software to support System 6) onto a floppy. I fed that floppy into my Mac IIsi and it mounted it cleanly on the desktop with no issues. I executed the installer and it ran to completion also with no issues. Following a restart, I had a full AppleTalk client installed AND a shiny new Network control panel, supporting the shifting of my AppleTalk connection between LocalTalk and EtherTalk.

Network Control Panel

So far, so good. If EtherTalk networking was the objective, we would be done at this point.

However, the objective is EtherTalk networking AND Internet connectivity, and so you need to proceed to the final step, which is installing MacTCP. In this case, you will want MacTCP 2.0.6, although an earlier version may work. When I expanded the .sit file for MacTCP 2.0.6, I got just a file called MacTCP. Presuming that this was either an extension or a control panel, I copied it into the System folder and restarted. Success! I now had a MacTCP control panel, supporting both LocalTalk and EtherTalk selections.

MacTCP Control Panel 01 with LocalTalk and EtherTalk

A word of warning at this point. If you are used to more “modern” TCP settings such as you might find in later versions of Mac OS, you may be unpleasantly surprised by MacTCP’s presentation. The Internet was a fairly new thing in System 6’s time, and this is reflected in the sometimes arcane settings that MacTCP 2.0.6 presents to you. It may take some inspired tinkering, and perhaps just a little time, to get MacTCP to configure the things you will want to configure, but rest assured – it can be done.

MacTCP Control Panel 02 Advanced Options

Regrettably, this article is being written after the fact from notes that I made at the time (as I write this, the Happy Macs lab remains in storage as part of our present corporate move) and so I can’t include specific instructions for each MacTCP control. However, I recommend setting your IP address manually (I’ve never had much luck with modern DHCP servers, such as you will almost certainly have in your cable/DSL box, and early versions of Mac OS), setting your subnet mask to, and setting both your Gateway address and your Name Server address to the IP address of your local home router (which will typically be your home’s cable modem or DSL box). was a common default address for many cable/DSL boxes for some time. Readers who have Comcast Xfinity boxes may find that works for them.

Anyway, with a bit of tinkering, I successfully bludgeoned MacTCP into configuring the settings I wanted and restarted my Mac. When the boot was finished, I was pleased to see that the Chooser control panel now “saw” the other vintage Macs on the Happy Macs Lab network (specifically those that were turned on and which had AppleTalk networking enabled) indicating that AppleTalk over Ethernet was up and running on my System 6 Mac.

System 6 Chooser w Quadra 840AV Selection

But better still, when I fired up MacTCP Ping, it not only successfully pinged the other Macs visible on the Happy Macs Lab network but ALSO successfully pinged multiple external web sites! My Mac IIsi was on the Internet!

MacTCP Ping

I had to sit back and marvel at this point. An incredible amount of newly installed hardware and software (the NIC card, its’ drivers, MacTCP and MacTCP Ping) had all just working perfectly – and in perfect harmony – the “first time out of the box”, allowing my Mac IIsi to reach outside the limited confines of the Happy Macs Lab and out onto the wild, wild west of the Internet. As I said earlier, the whole thing had been almost painfully easy.

Reflecting on that, being able to ping other servers on the Internet was perhaps quite a technology tour de force, but in the end, it is not terribly useful. So, what did one do with an internet-networked System 6 Mac “back in the day”? Why, one Gophered of course! Gopher, a very capable text-based precursor of the web, was THE way to share information at the time, and has been discussed at length in several earlier posts of this blog. System 6, as you may well guess, had an excellent Gopher client in the form of the third party program TurboGopher 1.0.8b4 (an earlier version of the TurboGopher 2.x series which features prominently in the aforementioned blog posts on Gopher).

I installed TurboGopher 1.0.8b4, fired it up and pointed it at the current “daddy” of Gopherspace, Floodgap Systems’ server (port 70). TurboGopher got right through and displayed their home page perfectly, if somewhat more slowly than I was accustomed to… which is to be expected I suppose – the Mac IIsi is a 20 MHz 68030 machine, after all.

Assuming that you have been following along and installing hardware and software on your machine as you go, from this point on, the internet is an open resource to your System 6 Mac. Remember however that the web is not! I have experimented with some of the very early web browsers that would run under System 6, but have had no (none, zero, nada) usable results. You can network your Macs, you can Ping Internet servers, you can FTP files and you can cruise through Gopherspace… but you cannot surf the web with your networked System 6 Mac.

So there you have it then! Networking your System 6 Mac with Ethernet can be a simple and enabling experience. Best of luck to you in your efforts in this regard!

p.s.> Networking via LocalTalk, on the other hand, has eluded me completely thus far! Just before the Happy Macs Lab was packed up, I was working on networking two System 6 Macs exclusively over LocalTalk, with no MacTCP involved, and was getting absolutely nowhere! I DID manage to connect to an ImageWriter printer I have using just LocalTalk, but that was as far as I could get. I could not get the two Macs to “see” each other over LocalTalk. This may become the topic of additional posts at a future time, once I figure it all out! In the meantime, just a word to the wise. It does not appear to be as simple to LocalTalk two or more Macs as it is to EtherTalk them over MacTCP.

p.p.s> All of the software mentioned in this post is available in the System 6 section of the Happy Macs Gopher server,, port 70… or rather, will be very soon. Regrettably, as I write this (April 2018), the Happy Macs Gopher server is presently offline due to our corporate move. However, it should be back on the net no later than the end of May 2018. Watch this blog for notification of its renewed presence. Until then, most, if not all, of the above mentioned software can be found on the web with a bit of luck and a lot of inspired Google’ing.


(Un)HappyMacs – A Mac IIsi and Gooey Caps

My recent interest in Macintosh System 6 led me to acquire a new Mac for the HappyMacs lab – a System 6 capable Macintosh with a larger screen (14” or more) than the rather diminutive one available on the Mac SE that was, up until this time, the only machine in the lab running System 6.


As I explained in my last post, I ultimately selected a Macintosh IIsi as my new “System 6 Engine” for the very pragmatic reasons that it was still relatively available on eBay, it did not cost the proverbial “arm and a leg” and it supported System 6 natively. Regrettably, I ran into trouble with this new acquisition almost immediately, and it took me more than just a little while to work through the universe of potential problems and zero in on what was actually going wrong.

Unhappy Mac - Color

As advertized, the machine arrived without a hard drive, but it did include a working floppy drive, and so it was immediately bootable. I have System 6 boot floppies from a separate purchase on eBay, and so I popped one in the floppy drive and powered up the machine for the first time. Unfortunately, it failed to boot (for reasons I did not understand at the time), and then to make matters worse, failed to eject the floppy. The mechanical floppy eject button did not do the job it was designed for, and I was reduced to gently prying the floppy out of the drive with a pair of needle-nosed pliers. This was not a good start!

I eventually did get the floppy out, and then worked through a succession of other sets of System 6 boot media until I finally experienced success… well, sort of. The machine finally did boot into one of the floppies I fed to it and presented a functioning System 6 desktop. Success! I thought… but only fleetingly. I quickly realized that the on-screen mouse pointer did not move when I moved the mouse. OK… lots of possible reasons for that… Bad mouse? Bad keyboard (the mouse was plugged into an ADB port on the keyboard, which was then plugged into the ADB port at the back of the IIsi)? Bad ADB cable? Bad system unit ADB port? Something else?

I slowly and methodically worked through all of the above, experiencing the occasional successful boot, only to be greeted by an inevitably “frozen” desktop in its aftermath. Eventually, I ruled out the mouse, the keyboard, the cable, the ADB port on the system unit, and even the monitor itself and was therefore left with only one possibility… something wrong with the system unit itself.

Mac IIsi Opened System Unit

That’s when I noticed “the goo”. Huh? …you are saying to yourself, “goo”? What in the world is “the goo”? Well, I am going to tell you! Anyone who enjoys the world of vintage Macintoshes has heard of the need to “recap” motherboards from time to time. This occasional necessity stems from the penchant of some aging motherboard capacitors (“caps”) to explode after many years of faithful service, severely compromising their intended function AND simultaneously spreading the electrolytic compound within them (the “goo”) all over their near vicinity on the motherboard.

Being aware of this, and starting to realize that the machine would never run for more than about a minute or so without freezing, no matter what I did (a behavior that sounded like a “cap” issue to me) I got out a flashlight and a magnifying glass and examined the motherboard in close detail. Sure enough, there was electrolytic “goo” on the motherboard in multiple locations. Sheesh! I had a “blown motherboard”! Below is a picture of one such site to give you a feeling for what this looks like.

Goo Site

I have bought no small number of vintage Macs on eBay and I have never received a bad one until now. I contacted the seller and he was very gracious about the whole thing. We agreed on a residual price for the re-usable parts in the machine and he refunded the difference. So, no damage had been done financially, BUT I had no “System 6 engine” either.

Recapping a motherboard is beyond both my capabilities and the facilities I have at hand, but I decided to try cleaning the goo off, hoping against reason that it was perhaps just shorting out some of the motherboard traces it was spread across. Such cleaning at least is easily done. All you need is some common rubbing alcohol and cotton swabs (such as Q-tips), both available at any local drug store (if not in your own medicine cabinet already!). Working slowly and carefully, I cleaned up all the goo sites I found. Below is a pic of a typical site I worked on:

Cleaning Goo

Eventually, I worked through a small bundle of Q-tips and was done. Would it work any better now? I powered it on, it booted up successfully… and it stayed booted! The mouse kept working and I was able to perform a successful shutdown for the first time ever. Thinking that I might have had the incredible good luck of dodging the “recap” bullet, I connected up the hard drive that was waiting to be added to the machine and powered it back on. This particular hard drive had a previously configured System 7 on it (to be replaced with System 6 as soon as possible, of course) and after a lengthy boot process, it presented its desktop and awaited my command.

I poked around in the control panels for a while, increasing the disk cache size and then enabling color for the display, and was honestly thinking to myself “well, this was too easy” when the mouse pointer froze once more! With a sinking heart, I tried again – no luck at all. No life at all. It would not boot. Here we go again…

To make a long story short, I discovered through trial and error that my motherboard cleaning efforts seem to have added about a minute or two to the system’s successful run time before it would again freeze. And freeze it would… and still does. Like clockwork, any session longer than two to three minutes results in a frozen machine. Unplug it and let it sit for about 4 hours and I can get another few minutes of run time out of it before it freezes again.

My conclusion? First, the motherboard definitely needs to be recapped, a roughly $125 undertaking when shipping in included. Second, the motherboard may not be the only issue. The power supply may also need to be recapped. I did not SEE any goo when I took it apart and examined it carefully, but that does not mean that there are not failed components in it. The time factor here (two the three minutes and then freeze) feels to me like how long it takes a damaged cap to either fully charge up or fully discharge – I am not sure which.

So, for now I have set this entire machine to the side and have purchased another one on eBay. It will be delivered shortly and I will try once again to establish a working System 6 test machine.

In the meantime, what can be learned from this experience of an unhappy Mac in the HappyMacs lab? Well I for one have learned to never again buy a Mac on eBay whose listing does not include pictures of the machine running its OS, and whose listing does not also include wording to the effect that it is fully operational. Otherwise, it is a case of caveat emptor (buyer beware)!