Macintosh System 6 – The Speed Demon of the Mac OS Family

I recently had cause to fire up my old Macintosh SE, one of the original all-in-one Macintosh models. It was donated to me by a family friend some years ago, but it was never of much interest to me, and as a result has spent more time gathering dust than doing anything else.

Macintosh SE

By today’s standards, the Mac SE’s screen is ridiculously small, and the lack of color seemed a curious omission, particularly given the emphasis Apple placed on the color capabilities of its cash cow Apple II. I have read that Steve Jobs was behind this decision (of course!), reasoning that since color printers were rare to non-existent for the average user of the day, the principle of WYSIWYG demanded that the Macintosh screen be similarly monotone. In the end, irrespective of the reasons behind its design decisions, a small screen, black and white device did not fire my imagination and it has spent the majority of its time sitting quietly on a back shelf in the HappyMacs lab since being donated…

…until recently. I needed some information on an old app that would not behave properly on any of my System 7 or later Macs. My long ignored Mac SE was running System 6, and so I set it up and powered it on. What immediately and absolutely impressed me about it was the speed of the machine! I know that saying “Macintosh SE” and “speed” in the same sentence may seem like a bit of an oxymoron, but the numbers bear it out. My Mac SE goes from power on to desktop in only 22 seconds, making it the fastest booting vintage Mac in the HappyMacs lab! In addition, applications seem to launch in a heartbeat and system shutdown is nearly instantaneous.

What lay behind this remarkable performance? Well, for starters the SE is rocking an Applied Engineering Warp 030 Motorola 68030 CPU accelerator. Research into the available Applied Engineering Warp 030 accelerators of the day revealed that both 40 MHz and 50 MHz models were produced. There are no utilities loaded onto the SE (yet) that can tell me what clock rate my SE’s Warp 030 is running at but I plan to find out in the near future.

M68030 at 50MHz

However, an accelerator alone is not enough to explain the speed. A 68040 is generally understood to be 2x to 3x the speed of an equivalently clocked 68030. Given this, if I assume that my SE has the fastest AE accelerator that was made for it, the 50 MHz model, then the performance of the SE should be in the same rough neighborhood as a 25 MHz 68040 based Macintosh. Happily, I have one of those, a Quadra 660AV, and I measured its boot performance: 63s from the end of its power on RAM tests to full desktop, approximately 3 times longer than the boot time of the Mac SE.

Astute users will quickly point out that this is not an apples to apples comparison (pun intended!). There might be RAM speed differences, there might be hard drive performance differences, and there definitely was a pronounced OS difference: the Quadra 660AV is running Mac OS 7.6.1 while the Mac SE is running Macintosh System 6.0.7.

System 6 About Dialog

This last difference is the one I want to focus in on, because I believe it is the true story here. I wasn’t really sure how to calibrate the impact of this difference however. System 6 is nearly a wholly unknown territory to me. My experience with Macs started with the early versions of System 7 and moved on from there.

I did a little web research and confirmed what the SE’s boot time suggested – System 6 is a speed demon, and despite its age, is still remarkably capable relative to its successor, System 7. System 6 ruled the Macintosh world from 1988 until System 7’s debut in 1991. During that period of time, Apple’s CPUs were clocked in the 8 MHz to 16 MHz region, RAM was expensive and not provided in generous amounts and hard drives were sized in the 10 MB to 100 MB range. In short, computers were relatively limited in the resources they provided, and their operating systems had to be in step with the constrained platforms they were deployed on. System 6 was light because it had to be!

This begins to explain the performance of my Macintosh SE. When you couple a (for the time) beefy 50 MHz 68030 with a light OS that is more in step with a 16 MHz CPU, you begin to experience real speed.

I decided to test this idea by pairing System 6 with a more typical machine of its day. I settled on the Macintosh IIsi as the test machine, a decision guided by the need to meet the very pragmatic requirements of (a) being reasonably available on eBay these days, (b) supporting System 6 and finally, (c) being clocked in the 16 MHz to 20 MHz range.

Macintosh IIsi

I will report on the results of my testing in an upcoming post. For now however, I will note that this particular post may not occur for a little while. The Macintosh IIsi I purchased on eBay almost immediately introduced me to one of the truly vexing problems associated with working on really early Macs – blown capacitors on the motherboard. My next post already has the working title of “(Un)Happy Macs”, and will concern itself with the issues I encountered, and how they were overcome.

Unhappy Mac

Also of some interest, as I started to dig into System 6, was the very real problem of loading software onto a non-networked older Macintosh that supports only dual sided 800K floppies, a media type that has long since disappeared from both Macintosh support and public consciousness. I found two interesting workarounds and will share those in another upcoming post.

Box of 800K Floppies (398x356)

Until then, my limited work with it to date suggests that System 6 is a remarkable OS, so light that it practically floats, and yet so capable that it will run all the major applications of its day in the blink of an eye, and even get you on the internet! If you haven’t tried it out, it may be worth your time. More to come…