The Soul of An Old Machine – Quadra 840AV Lives and Breathes

The Soul of An Old Machine - Quadra 840AV Lives and Breathes

68040 at 40 MHz – Blistering! 🙂

…with apologies to Tracy Kidder, after whose excellent book “The Soul of a New Machine” this post’s title is patterned.

After sputtering and wheezing a few times, the Quadra 840AV chimed back to life again this weekend, still sporting its CD munching CR-ROM drive and its incredibly FR (floppy retentive!) floppy drive, but successfully booting Mac OS 7.6 once more. By the time the weekend was over, it had received a significant makeover. In the aftermath of the weekend’s work, the hard drive has now been updated to the replacement 4.5 GB unit, the CD-ROM drive has been replaced with one that will actually mount AND eject CDs, and Mac OS 8.1 is now loaded and running on the machine. From a hardware perspective, only the floppy drive remains to be replaced and that aspect of the work will be done.

I titled my last post about this topic “The Need for Speed”, and while it may seem silly to use the word “fast” in conjunction with a machine whose speed is measured in MHz not GHz, I have to say that this machine is FAST. After working extensively with my 25 MHz Quadra 660AV, the 40 MHz 68040 in the Quadra 840AV just races through Mac OS initialization and launches apps in what seems a fraction of the time it takes on the 660AV. Of course, in addition to the faster CPU, my Quadra 840AV has a different and potentially faster hard drive, and also features the hardware enhancement of interleaved RAM, both of which accelerate throughput. Nonetheless, the subjective result is pretty tangible. This machine is FAST!

It is not quite as fast however under Mac OS 8.1 as it was under Mac OS 7.6. There is a definite performance penalty for moving up to Mac OS 8.1, but it is worth it, if only for simple features like “sticky menus” (when you click a menu, it stays there without you having to continue to hold down the mouse key) and what we know today as “right click context menus”, although on Mac OS 8.1 that is “control click context menus”. The net result of this and a whole host of other incremental improvements is that Mac OS 8.1 is an easier to use and more pleasant environment than Mac OS 7.6 was – I can see why Mac OS 8 sold so well in its day (it sold an amazing 1.2M copies in its first two weeks!).

Mac OS 8.1 brought the now standard Mac OS Extended file system to Macs, delivering key enhancements like file names that were greater than 32 characters long and support for larger drives. In the Quadra 840AV’s day (1993), when DOS and Windows were still struggling with the old 8.3 file name format, Macs were light years ahead of them with their 32 character filenames, and no need for an extension as part of that. Mac OS Extended relaxed even the 32 character limit, but this was no longer a competitive advantage, as Microsoft had finally caught up with Apple in this regard by the time Mac OS 8 was released in 1997.

Mac OS Extended is great, but a word to the wise. 68K Macs cannot boot off of a Mac OS Extended partition, and so when I installed Mac OS 8.1 onto the new larger replacement hard drive, I had to partition the drive into two, with the first smaller partition being a boot partition (I made it 1 GB) using Mac OS Standard. The remaining 3.5 GB of the drive were put into the second partition, which used Mac OS Extended. Having a Mac OS Standard boot partition on a 68K Mac is simply a requirement, so keep this in mind if you ever decide to put a larger drive into a 68K Mac running Mac OS 8.1.

Keep in mind as well that the Mac OS 8.1 installer isn’t all that “smart” about it. After I configured the partitioning and the installer went about its task, it eventually paused and informed me that “the selected partition can only be used to boot PowerPC Macs”. Hoping it was referring to the second partition, and that my first partition would be bootable after the installer was done I proceeded, but the message was both misleading and disconcerting. I can honestly say that after the two hours or so it took the installer to do its job (I had it install EVERYTHING on the Mac OS 8.1 CD), I almost literally held my breath as I put it through its first boot – thank goodness it worked and I didn’t have to start over, with the whole drive partitioned for Mac OS Standard!

One other thing will be of interest if you ever upgrade an old Mac with a new hard drive. At least for the Quadra 840 AV, but generally for all older SCSI-based Macs, you will need to set the new drive’s SCSI ID to (typically) zero and also ensure that the drive provides SCSI bus termination. Since this is done differently on just about every drive you will meet (even within one manufacturer, the mechanisms for doing this will vary from drive to drive) you will need to find the manual for the drive you are using and read up on how to configure these things. Happily, even after all these years, manuals for old hard drives can normally be found reasonably quickly after a bit of Google’ing around.

Usually, there is a jumper block somewhere on the drive that allows you to configure both the SCSI address and SCSI bus termination. This was the case for the drive I used, where there were jumper blocks both on the back of the drive and one on the logic board of the drive. I didn’t set the jumpers initially, and when I tried to boot it, the Quadra just sat there, showing no signs of life whatsoever after the chime – no “happy Mac”, no “sad Mac” … nothing. I had to deduce that the jumpers must be wrong, take the machine apart, pull the drive out, and re-examine all the settings. Sure enough, the termination was not set correctly. Once I got that right, everything started to work.

So, the Quadra 840AV lives and breathes. Next up will be to load some key software (Microsoft Office 4.2 and Photoshop 4.0) and change out the floppy drive – it will be nice to have a drive that actually eject floppies, instead of having to use pliers to pull them out.

Looking back, what have we learned? Lets see… 40 MHz 68040s are (comparatively) FAST, Mac OS 8.1 is a worthy (but slightly slower) upgrade over Mac OS 7.6, you can’t boot a 68K Mac off of a Mac OS Extended partition and finally, terminate your SCSI bus if you wish to change out a hard drive on a SCSI based Mac.

That’s it for this time. I will report back again when I have further progress.

2 thoughts on “The Soul of An Old Machine – Quadra 840AV Lives and Breathes

    • Quadra 840AVs are most definitely on the “rare Macintosh” list at this point. I (im)patiently watched eBay for well over a year before finding one myself, and I honestly can say that I haven’t seen one on eBay in a very long time. I am told that estate sales are good place to find vintage Macs, so you might wish to try that, but that is rather like looking for a needle in a haystack. Other than that, all I can recommend is watching eBay like a hawk, and pouncing when you see one.

      If any of the readers of this blog have a Quadra 840AV that they would like to sell, please let me know and I will make the necessary connections. In one of the comments to one of my posts, a reader ( recently indicated that he had an 840AV for sale, but my follow on questions got no response, so it may be sold already. Nonetheless, you may wish to try contacting him and see if it is perhaps still available.

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