Thanks for the detailed primer/tips MusicWorks! 
You are welcome mrhappy
What sort of system configuration was allowed with the SA8/442 combo under 4.01? Was it supposed to be a secondary device with an 88x present as a master on a Disk I/O, or was this a last-gasp standalone kinda thing?
The Bridge IO allows extra inputs and outputs to be added to the system, but take into account a 88x interface needs to be present at all time on the Disk I/O connector. The SA8 will effectively "bridge" those new inputs and outputs to/from the Disk I/O -through the internal TDM cabling. Thus, unlike the addition of a second Disk I/O, it does not require it's own hard drive. Because of this, a total of 8 inputs will be capable of recording *simultaneously* in spite of having a total of 12 inputs (8 from the 88x, and 4 from the 442).
In this configuration you would have:
- Disk I/O NuBus card in the lowest slot = connected to 88x interface
- DSP TDM Farm NuBus card in the middle slot
- SA8 Bridge card in the highest slot = connected to 442 interface
All of them properly connected with a TDM ribbon and terminated. I can post scans of the PT4 manual if anyone is interested in the "Hardware Setup" chapter. Please note PT4 was a software only upgrade, so any PT4 system is effectively a PT3 system with newer software
I was quite surprised myself to find such information on the forums, as I had avoided upgrading to PT4 because I needed to drop my 442s from the system -and was not so happy about that idea at all. As I said I really like it's AD, and I am usually very picky with AD's.
Newer converters sound so sterile and not musical at all...and most of the older converters give a much cleaner sampling with an external clock (I love my Mini-Me). After tracking a SA-8 card, I decided to go through the upgrade knowing I could still use my 442 as main inputs for the system.
Answering your question about the system this was installed in, it is a 7100/80 with a 240Mhz NewerTech G3 upgrade. This guide would be essentially identical for your 9150/80 (A WGS Workgroup Station? You are a lucky man, you know that!?
) And I would choose NewerTech over Sonnet too.
About the Mac OS version and the 8.1 / 8.6 dilemma. And of Macintosh OS development in general. Everyone in these forums need to understand that OS9 is simply the last revision of a very old operating system that started out as System 6. After that, System 7 was the consolidated version that was developed for almost a decade from the 7.0 "Golden Master" to the 7.6.1 -last revision of System 7.
At about that time, Apple was doing the I+D on "Copland", which they intended to be their new operating system. Mac OS 8.5 was a major rewrite on the OS core, which included many of the technologic advances they wanted to include in Copland. The filesystem had an extension rewrite (Mac OS Extended) that was included in 8.1, last version compatible with old rom 68k and first one to use the Mac OS Extended filesystem intended to optimize the available space for larger drives. Major file corruption problems arose with 8.5, and were "patched" in 8.5.1.
Pro Tools 4.0 was officially *tested* with 7.5.3 and 7.5.5 and was officially *supported* in 8.0, 8.1 and 8.5.1.
8.6 is very likely to work, however there are a few things to take into consideration:
On a hardware level, 68k Motorola processors were deprecated and replaced by the newer PowerPC 603 processors, and most of the older 68k kernels were ported to PPC in OS8 / 8.1. You need to understand that given CPU technology and it's implementation was changing so rapidly, most -if not all- of the code of System 7 is written for 68k. Mac OS 8 is essentially the same operating system, with kernel and finder ported to PPC.
That is why 99,99% of software designed and tested for System 7 is fully compatible with 8.0 and 8.1. It's also interesting to note 8.1 is the *last* version to run on 68k macs. Why is so? Because the main task processors were finally ported to PPC in 8.5. If you try to run 8.5 in a 68k computer you will get the sad mac face.
In a way, operating systems needed to be "hybrid" to work both in 68k and PPC computers. In System 7 with the use of a PowerPC Enabler (that is, essentially an "emulator" to run 68k code in a PPC core) and in Mac OS 8 with native PPC code.
Pro Tools 4.0 was optimized for PPC processors, and was officially tested in 7.5.3 and 7.5.5. When the native PPC kernels were released with OS8 people realized that PT4 was running better than ever. Finally a PPC optimized Pro Tools in a PPC compliant operating system. Waveform redraws were barely perceptible
Having said this, PT4 runs very happily in OS 8.1 and from what I have read many many films were cut in such systems (7100 or 8100, with PT4 and 8.1).
There is an analogy of the "hybrid" operating systems and the more recent transition from PPC to Intel processors. 10.5 "Leopard" is a classic example of a Macintosh "hybrid" system that runs beautifully both in modest PPC computers as well as in Intel 8-core or 12-core Mac Pro machines. 10.6 "Snow Leopard" was effectively an Intel only version of Leopard with stripped PPC code -all kernels ported for the new Intel multicore machines.
In many ways, 10.5 Leopard is superior than 10.6 Snow Leopard. Not to mention the newer iPhone like revision of the OS, which are simply ridiculous from a Pro user perspective. Most workstation in film postproduction today still on 10.5 Leopard, rarely some on 10.6. It's solid.
If you want to install 8.6, makes sense if you want to use several machines with same OS, I would install 8.5 first. Then update to 8.5.1 -and then update to 8.6. It's been mentioned several times in the forums that some users going directly from 8.5 to 8.6 were having problems. Either that or a clean install of 8.6. Please note this version was never supported for PT4.0.
I have used 8.6 extensively in the past, and it's a solid OS. It should work.
My god...I get so technical at times I almost forget I am in this for the music!!!!!!
Experience and logic helped me figure most of this out. I find it funny when people talk about OS9 as a separate entity, when it is quite simply System 7 on steroids.
- MusicWorks
