Dialectronics - the dialect of electronic communications





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PowerPC

Lua

XCOFF Bootloader

Old World Macs

Open Firmware

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Recent News:

6/17/07: Since there's been some interest in Beginning Open Firmware Debugging Techniques, Part I, we decided to go ahead and post Beginning Open Firmware Debugging Techniques, Part II, although in some places it is a bit rough. Better to at least get the information out there rather than let it sit somewhere unavailable to someone that might gain from it. If you wish to help polish either piece, drop us a line.
6/5/07: We're baaaaack :-) We came to realize that we can ignore our spots but that doesn't make them go away. What's new? OpenBSD finally caught up us (after two years) and started supporting Old World Macs. We've seen a noticeable increase in traffic since then (and noted to ourselves the connections from Calgary during the 2006 hackathon).

We have decided to take the plunge and develop our own operating system, based on exokernel design. The focus will be RISC-based CPUs, with initial development on PowerPCs (Old World Macs, of course). If this wasn't difficult enough, we have decided to do it with end-to-end MIT/BSD/public domain licensed source code, including the compiler. To add to the workload, we also decided to develop a programming language that inherently optimizes RISC-based CPUs, through a register-centric mentality instead of the common stack-centric philosophy. We're looking for four or five individuals that would like to participate in this project. Applicants must have strong left-wing beliefs, be willing to accept decisions made (with or without debate) by a central authority, and have a desire to do something completely different in a world where homogeneity is not only expected but imposed (by force if necessary). Programming experience is not a prerequisite (it might even be a hindrance), but a commitment to excellence is. If this sounds like something you are interested in, drop tim (English) or timo (German) an email describing your beliefs and experiences. If you are unable to locate either email address, you probably won't fit in, due to the extensive research requirements this project will have.
1/23/07: Well, what to say? We've generally packed it in and moved on. We're preparing a closing statement, but other activities keep us too busy to spend much time on it. In general, we have left computers and moved into Green building practices. We'll post more information directing visitors to that site soon.

Otherwise, the only significant changes are moving to OS X running lighttpd (one of the few installs in the world) for web serving and postfix for mail with postgrey for anti-spam measures. Lighttpd mysteriously dies every couple of days, but otherwise the package works well. The move to OS X was precipitated by an effort to reduce our CO2 footprint as much as possible, and the NetBSD box was redundant and underused. We're not big fans of Apple, but NetBSD's power management is very poor and the Mac mini was on all of the time anyways.

We did post the NetBSD-ready version of the PowerPC-optimized bcopy/memcpy. You can find it in the PowerPC corner.

We're quite excited about the new direction we're taking. It builds on some of our past experiences in home repair field coupled with some financial planning theories we've developed (your house is your greatest asset) and the coming revolution in Green building. We'll post more when time permits.

7/18/06: Perhaps it is the summer heat and we've gone crazy, but we've posted the first installment of the never before published "Open Firmware Debugging Techniques," which was supposed to be the intro to the unpublished "This Operating System, That Hardware" series on porting NetBSD to a JS20. Part I deals with the command line interface to Open Firmware. Enjoy.
7/7/06: Updated the bcopy/memcpy code. Turns out there was a bug in the original code that caused errors with copies of less than 4 bytes when the destination address was higher than the source address (backwards copy). We've tested a kernel compiled with the code and it works. Next up is a userland and libc build.
5/31/06: Even more amazing! tim found time to post the first three installments of the "Some Assembly Required" series that did not get published by developerWorks. They can be found in the PowerPC area. What's next, posting the first two installments to "This Operating System, That Hardware?"
5/31/06: Gee, tim found some time to gather some links to work he's done as a technical editor and as a writer. They can be found in the new Words area.
5/28/06: While he hasn't had time to fully finish it, tim has posted a faster bcopy/memcopy routine to the PowerPC section. It's about 10% faster for aligned copies and about 80% faster for unaligned copies. The main holdup for releasing it in a bcopy/memcopy form is that these routines are in the string libraries that are linked against extensively. We haven't had time to do a complete rebuild, and simply replacing the recompiled libraries led to segmentation faults (not the fault of the code but the changed linking locations).
5/5/06: It's been a long time coming, but we've moved our mail and web servers from MacOS 9.x and Webstar to NetBSD with lighttpd, cyrus and postfix. We're using NetBSD 3.99.3 with several custom code components. Eventually Tim will find time to write them up. Lots of news regarding the QZ! Engine (two deployments) and his efforts to be a published technical writer, but time is short as always. One day...
10/27/05: Action in the background has been fast and furious, but nothing for print yet. We've got news approaching on the status of QZ! 1.0, our assessment database system, and lots to report on the operating system research we've been doing. However, until we can talk about it, we'll hope the new Journeys section (ok, re-release of old classics) will make the wait worthwhile.

9/2/05: Updated bootloader page.

6/27/05: We've moved our web and mail servers in-house. If you have trouble emailing someone here, please use our web form. Updates should follow shortly, including the newest features to the modified bootloader.

10/19/04: Pre-release (unsupported, available for testing) of boot25c.xcf. Further decoupling of kernel location from bootloader location; the bootloader has to be on an Open Firmware readable partition while the kernel can be on either OF readable or an MBR/FFS partition.

8/28/04: Pre-release (unsupported, available for testing) of boot25a.xcf. Initial support of decoupling of kernel location from bootloader location; local stack instead of Open Firmware provided.

8/22/04: Three new areas have been opened. The first is the release of a generic bootloader for NetBSD and OpenBSD. This XCOFF bootloader will work on both Old and New World Macs and does not require altering Open Firmware settings except where kernel loading issues require it. The second area is a discussion of several issues to be overcome when porting an operating system to Old World Macs. As proof of concept, there is also a working OpenBSD 3.5 RAMDISK shell for Old World Macs. Third, as an outgrowth of both of the two previous areas, there is an area for PowerPC processor research, including code for dynamically calculating the L2 cache size on G3 and G4 CPUs.

2/27/04: The screenshot of the login hole in OS X is here. A discussion of the hole can be found beginning at Macintouch.