Brasstacks

Using my MacIvory, until now, I have been using an old Mac Powerbook running Mac OS 9 with AppleTalk file-sharing to allow me to copy files from a USB key to the Mac IIfx host running 7.6.1. Trying to access shared folders on my newer laptop running Mac OS X failed, as did sharing in the opposite direction. Presumably, the problem is that Mac OS X uses a revision of the AFP file-sharing protocol which is incompatible with the version used by the default Mac OS 7.6.1. It turns out there is a fix for this issue: Install Open Transport 1.1.2 (a dependency for the next step) on the 7.6.1 Mac Install AppleShare Client 3.8.3 on the 7.6.1 Mac The Apple article on AppleShare Client 3.8.3 has more information on this release of the software. Apparently AppleShare 3.8.8 requires System 8.

Working with ResEdit and DeRez, I believe I have traced out the keyboard protocol used by the MacIvory ADB adapter . My adapter is on the blink, probably because of the small screw I found rattling about inside. I hope DKS can bring it back to life, or the PIC-based project I had begun will make its way back to the front burner.

The ADB adapter has not just given me some help uncovering the behavior of the Rev. C Symbolics keyboard protocol, but also works when attached to my MacIvory. Along the way (and with the help of David K. Schmidt) I encountered some glitches, mostly stemming from my original accidental trashing of the System file DKS installed. There are a few software components the ADB adapter box needs to convert the Symbolics keyboard to something the Mac OS 7.6.1 (including the "FEP" window which communicates to the Ivory board on a low level) will accept as a keyboard with the right keymapping, and furthermore to something the Genera application will recognize with all the Symbolics-specific keys. Without these components, you will see one of the following two stages of malfunction. Stage 1: The mouse connected to the ADB adapter works fine. In the Mac OS (including the FEP window), there is total keyboard confusion, with the keys all scrambled. On the Genera side, things are less ...

A few comments about the PICkit 2 learning experience. There's a slight bit of polish that could be applied to the example code. A few redundant instructions, such as Extraneous operations setting register pages In A-to-D examples, the data sheet seems to say the 5 microsecond settling time is needed only when changing the input source, not for every conversion, as in the examples For the 5 microsecond interval, a few of those microseconds are covered by the non-NOP instructions before the conversions In one of the variable-speed rotating bits examples, the carry flag is not explicitly cleared when it needs to be clear. When I modified the example to change the sign of the pot setting-to-delay conversion, I would sometimes set the carry, putting extra bits into the display. Took me a good fifteen minutes to debug that. I think a few extra instructions are wasted using the W register and an explicit move to the file register when the file register destination could be...

My latest diversion is a Microchip PICkit2. The idea is to make something that can understand the Symbolics keyboard I have, and then connect that something to other things that can speak Apple Desktop Bus (ADB), PS/2 keyboard protocol, or USB, in roughly that order. If I can make something that takes a multi-button PS/2 mouse and a Symbolics keyboard and connects both to a MacIvory, I could be set for beautiful three-button mousing and classic keyboarding on my Lisp Machine. I've mostly traced out the schematic of my Rev. C Symbolics slim-line keyboard (thank god for simple two-layer boards!). Rev. C has LED's in the Caps Lock and Mode Lock keys, in contrast to this picture of the similar Symbolics Rev. B keyboard . Compared to the Symbolics 3600 keyboard schematic , mine is roughly similar, but unfortunately has a 40-pin microcontroller (an Intel 8749H, a member of the MCS-48 family) soldered in. I am certain I could make something work with the simple protocol the 3600 key...

I've only had a bit of time to play with my MacIvory, but already things are getting interesting. One is getting used to the system administration style: typical UNIX system configuration resides in text files, and the boot process reads them. Genera is different. The state of the system is contained in the memory image ("world"); you change it through various operations---some interactive, some by loading Lisp files---and preserve it by saving a new world as a file, which can be defined incrementally based on an existing world. The boot process involves loading that saved file back into the living Lisp machine. I haven't yet developed the sense to complete a block of tasks before saving the world, and how much change pushes one from incremental to a complete world. Another was getting the network to speak, and part of that is the timewarp of working in Mac OS 7, an era in which Mac networking was going through the introduction of Open Transport, and an AppleTalk era ...