Newsgroups: comp.os.linux.announce Path: bga.com!news.sprintlink.net!uunet!MathWorks.Com!news.kei.com! travelers.mail.cornell.edu!cornell!bounce-bounce From: para...@sousa.amt.ako.dec.com (Jim Paradis) Subject: Linux/AXP Progress Report Message-ID: <ann-15996.779393888@cs.cornell.edu> Followup-To: comp.os.linux.misc Keywords: AXP, DEC ALPHA kernel port Sender: m...@cs.cornell.edu (Matt Welsh) Reply-To: para...@sousa.amt.ako.dec.com (Jim Paradis) Organization: Digital Equipment Corporation, Acton MA Date: Mon, 12 Sep 1994 18:18:28 GMT Approved: linux-annou...@tc.cornell.edu (Matt Welsh) Lines: 165 [] Linux/AXP Progress Report September 9, 1994 Jim Paradis Alpha Migration Tools Group Digital Equipment Corporation Introduction - What Is Linux/AXP? The Linux FAQ (Frequently-Asked-Questions) list describes Linux as follows: Linux is a Unix clone for 386/486-based PCs, written from scratch by Linus Torvalds, with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX compliance. It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management and TCP/IP networking. It uses the hardware features of the 386 processor family (TSS segments et al) to implement these features. It is distributed under the GNU General Public License Although the distributed Linux kernel depends heavily on the x86 processor architecture, it is feasible to port it to other architectures. Indeed, ports are currently in progress to the Alpha AXP, 680x0, PowerPC, MIPS, and possibly other architectures. Linux/AXP is my port of the Linux operating system to the Digital Alpha AXP architecture. Overview of Linux/AXP Linux/AXP is a port of Linux to the Digital Alpha AXP RISC microprocessor. It is based on the Linux V1.0 kernel. Linux V1.0 was current when I started the project. To limit the number of variables, I decided to stick with a single version while developing the AXP-specific pieces. Although the Linux V1.0 kernel provides more than enough functionality for our current needs, we might investigate subsequently leapfrogging to the most-current stable kernel when Linux/AXP is stable. Linux/AXP is a 32-bit operating system. Except for those cases where the kernel must interface with the Alpha AXP hardware, no kernel data type is wider than 32 bits. As far as C programmers are concerned, so pointers and longs are 32 bits. The decision to remain with 32-bit data types was based on our group's experience with migrating legacy software to a 64-bit environment. By not changing the size of any data types, those parts of Linux that are unaffected by the port (such as the file system code) should continue to work without modification. Changing the data type size would require significant code review to ensure that all data types are used correctly. Note that 64-bit quantities are still available for computation through the use of "long long" and "long double" C data types. Thus, the only limitation of a 32-bit operating system is the unavailability of 64-bit pointers. On PC-class machines, with at most a few tens of megabytes of physical memory, this should not be a significant restriction for the forseeable future. Linux/AXP is primarily targetted at PC-class Alpha AXP platforms that support ISA, EISA, VLB, and PCI devices. Support for other devices and platforms is possible in the future. Contributions of drivers for other platforms are always welcome. Current Project Status I am currently cross-developing the Linux kernel port on a DEC 3000 model 500 AXP that is running DEC OSF/1. I have also built and tested all of my development tools on a 486 box running Linux, and everything seems to work there too. Naturally, I prefer the Alpha AXP box 8-). The cross-development environment consists of gcc 2.5.8 with configuration options for "alpha-linux", as well as gas, gdb, ld, and GNU binutils. I modified gdb has been modified so as to allow source-level debugging of Linux when running on the ISP software simulator. ISP is an Alpha AXP CPU software simulator that runs on Ultrix, DEC OSF/1, Linux, OpenVMS, and Windows NT AXP. Only the DEC OSF/1 and Linux versions support remote debugging via gdb. The development environment also includes a set of utilities for viewing and manipulating ext2 file systems from user mode. These are necessary when creating a bootable file system image for Linux/AXP. The Linux kernel currently boots, goes through all initializations, and runs the first user task. At present, that first user task is a hand-crafted "hello, world" program in place of /etc/init. A more significant program is not available, due to the unavailability of libc. Porting libc has been taking place in parallel with kernel development and porting user and system utilities is taking place now. Linux/AXP currently boots from a 1.44Mb ext2 floppy or floppy image. Linux/AXP does not yet have disk drivers. The bootstrap code reads the floppy image into a RAM disk area, and the kernel uses the RAM disk as its root file system. The bootstrapper takes the RAM disk size from the file system; the size of the RAM disk is limited only by available system memory. Future directions Currently I'm getting a core set of utilities (sh, ls, grep, cat) up and running, and packaging up a "developer's kit" for those who would like to contribute to the project. The developer's kit will consist of: - Sources for the Linux/AXP kernel - Sources for all cross-development tools (gcc, etc) - Sources for the ISP AXP CPU simulator - Porting notes, build instructions, etc. The developer's kit will definitely work on DEC OSF/1 systems and Intel Linux systems. It will probably run on other UNIX systems as well, but I cannot guarantee that. The version of Linux in the developer's kit will probably have only console-callback device drivers. Console-callbacks are the Alpha AXP equivalents of BIOS calls on an Intel system. They are quite slow because they run synchronously with interrupts disabled. As on an Intel system, using console-callback or BIOS drivers will get you up and creaking, but an important item on the agenda will be to write real device drivers that take full advantage of the system and the Alpha AXP CPU. The supplied console-callback drivers will only support local disk and console character I/O. No networking, graphics, or windowing support will be available. Distributed utilities will be minimal and the kernel itself will be extremely fragile. The developer's kit will be distributed via anonymous ftp, with the location to be announced. If you would like to contribute to the Linux/AXP project, please send email to para...@amt.ako.dec.com. I will maintain a list of who is working on what, to reduce duplication of effort. Please note that in order to do useful work in the device-driver space, you MUST have access to an ISA or EISA-based Alpha AXP system (such as the DEC 2000 AXP). Unfortunately, we are not in a position to lend out development systems at this time, except to Linus of course 8-). Questions/comments/requests please to para...@amt.ako.dec.com. -- Jim Paradis (para...@tallis.enet.dec.com) The purpose of time is to keep everything from happening at once. It's not working. -- Send submissions for comp.os.linux.announce to: linux-annou...@tc.cornell.edu Be sure to include Keywords: and a short description of your software.
Path: nntp.gmd.de!xlink.net!howland.reston.ans.net!pipex!sunic! news.funet.fi!news.csc.fi!news.helsinki.fi!not-for-mail From: para...@sousa.amt.tay1.dec.com (Jim Paradis) Newsgroups: comp.os.linux.announce Subject: Linux/Alpha Progress Report - Part 1 Followup-To: comp.os.linux.development Date: 18 Nov 1994 20:12:50 +0200 Organization: Digital Equipment Corporation, Littleton, MA Lines: 87 Sender: wirze...@cc.Helsinki.FI Approved: linux-annou...@tc.cornell.edu (Lars Wirzenius) Message-ID: <3aiqr2$nog@klaava.Helsinki.FI> NNTP-Posting-Host: klaava.helsinki.fi Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Keywords: Linux, kernel, Alpha, Digital, port, development, progress report Linux/Alpha Progress Report Part 1 - Overview November 14, 1994 Jim Paradis Alpha Migration Tools Group Digital Equipment Corporation NEW EMAIL ADDRESS: para...@amt.tay1.dec.com 1.0 INTRODUCTION - WHAT IS LINUX/ALPHA? The Linux FAQ (Frequently-Asked-Questions) list describes Linux as follows: Linux is a Unix clone for 386/486-based PCs, written from scratch by Linus Torvalds, with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX compliance. It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management and TCP/IP networking. It uses the hardware features of the 386 processor family (TSS segments et al) to implement these features. It is distributed under the GNU General Public License Although the distributed Linux kernel depends heavily on the x86 processor architecture, it is feasible to port it to other architectures. Indeed, ports are currently in progress to the Alpha, 680x0, PowerPC, MIPS, and possibly other architectures. Linux/Alpha is my port of the Linux operating system to the Digital Alpha architecture. 2.0 OVERVIEW OF LINUX/ALPHA Linux/Alpha is a port of Linux to the Digital Alpha RISC microprocessor. It is based on the Linux V1.0 kernel. Linux V1.0 was current when I started the project. To limit the number of variables, I decided to stick with a single version while developing the Alpha-specific pieces. Although the Linux V1.0 kernel provides more than enough functionality for our current needs, we might investigate subsequently leapfrogging to the most-current stable kernel when Linux/Alpha is stable. Linux/Alpha is a 32-bit operating system. Except for those cases where the kernel must interface with the Alpha hardware, no kernel data type is wider than 32 bits. As far as C programmers are concerned pointers and longs are 32 bits. The decision to remain with 32-bit data types was based on our group's experience with migrating legacy software to a 64-bit environment. By not changing the size of any data types, those parts of Linux that are unaffected by the port (such Linux/Alpha Progress Report Page 2 as the file system code) should continue to work without modification. Changing the data type size would require significant code review to ensure that all data types are used correctly. Note that 64-bit quantities are still available for computation through the use of "long long" and "long double" C data types. Thus, the only limitation of a 32-bit operating system is the unavailability of 64-bit pointers. On PC-class machines, with at most a few tens of megabytes of physical memory, this should not be a significant restriction for the forseeable future. Linux/Alpha is primarily aimed at PC-class Alpha platforms that support ISA, VLB, and PCI devices. Support for other devices and platforms is possible in the future. Contribution of drivers for other platforms is always welcome. -- Jim Paradis (para...@amt.tay1.dec.com) The purpose of time is to keep everything from happening at once. It's not working. -- Send submissions for comp.os.linux.announce to: linux-annou...@tc.cornell.edu PLEASE remember Keywords: and a short description of the software.
Path: nntp.gmd.de!xlink.net!howland.reston.ans.net!spool.mu.edu! uwm.edu!lll-winken.llnl.gov!decwrl!pa.dec.com!sousa.tay1.dec.com! sousa.tay1.dec.com!not-for-mail From: para...@sousa.tay1.dec.com (Jim Paradis) Newsgroups: comp.os.linux.development,comp.os.linux.misc Subject: Linux/Alpha Progress Report - Part 2 Date: 14 Nov 1994 14:43:11 -0500 Organization: Digital Equipment Corporation, Littleton MA Lines: 284 Distribution: world Message-ID: <3a8ekf$oeq@sousa.tay1.dec.com> Reply-To: para...@amt.tay1.dec.com NNTP-Posting-Host: sousa.tay1.dec.com.amt.tay1.dec.com Linux/Alpha Progress Report Part 2 - Current Status November 11, 1994 Jim Paradis Alpha Migration Tools Group Digital Equipment Corporation NEW EMAIL ADDRESS: para...@amt.tay1.dec.com 1.0 SUMMARY OF CHANGES SINCE LAST MONTH: o Linux/Alpha now boots to shell prompt. o Linux/Alpha is no longer called Linux/AXP (in keeping with current company policy). o New addresses for email contact. o Linux/Alpha now runs off the hard disk -- no RAMdisk needed. o Development problem with floppy disk booting support. o Release of software development kit imminent. o Call for developers. 2.0 PROJECT GOALS AND ENVIRONMENT The current goal of the Linux/Alpha project is to produce a software development kit (SDK) that will enable members of the Linux community to do kernel, utility, and application development for Linux/Alpha. The first release of the SDK should take place by the end of the year, and it will be directed primarily at kernel and device driver developers. I am currently cross-developing the Linux kernel port on a DEC 3000 model 500 that is running DEC OSF/1. I have also built and tested all of my development tools on a 486 box running Linux, and everything seems to work. Naturally, I prefer the Alpha box 8-). The cross-development environment consists of gcc 2.5.8 with configuration options for "alpha-linux", as well as gas, gdb, ld, and GNU binutils. I modified gdb to allow source-level debugging of Linux when running on the ISP software simulator. By the time the SDK is released, I hope to have gdb working over a serial line to an actual Alpha processor, running Linux. ISP is an Alpha CPU software simulator that runs on Ultrix, DEC OSF/1, Linux, OpenVMS, and Windows NT AXP. Only the DEC OSF/1 and Linux versions support remote debugging via gdb. Linux/Alpha Progress Report Page 2 The development environment also includes a set of utilities for viewing and manipulating ext2 file systems from user mode. These are necessary when creating a bootable file system image for Linux/Alpha. 3.0 NEW CONTACT ADDRESSES Because of another office move, my email address has changed. If you wish to send me email, use: para...@amt.tay1.dec.com In addition, I have created a mailing list for all who are interested in the Linux/Alpha project. The mailing list address for general discussion is: linux-...@amt.tay1.dec.com If you have sent me mail in the past regarding the Linux/Alpha project, then you should be on that list. If you don't receive the initial greeting within the next week, or you have any other administrative request, send mail to: linux-axp-requ...@amt.tay1.dec.com 4.0 FLASH!! LINUX BOOTS TO SHELL PROMPT! The biggest news since the last report is that the Linux kernel now boots to a shell prompt. Currently "init" is a simple stub program that runs the shell. The shell currently in use is "rc", the Plan 9 shell. I chose this shell because it was the first freeware shell I found that compiled cleanly on my somewhat cantankerous cross-development environment 8-) Speaking of cross-development...the biggest headache I've had has been using configuration scripts. Many scripts have only a limited (or no) concept of cross-development. Often, one ends up with something that's fit neither for the host system nor the target system. I now have an Intel Linux box networked to my development system. I perform the configuration on the Linux box, the modify the makefiles to reflect teh cross-development environment. I have managed to port several utility packages this way: basename, cat, chgrp, chmod, chown, cp, du, echo, expr, head, ln, ls, mkdir, mv, od, rm, rmdir, tail, touch, tr, wc I hope to port a few more utilities before the SDK is released. Linux/Alpha Progress Report Page 3 5.0 NOW RUNS OFF THE BOOT DISK. Since the last report, there have been some changes in bootstrapping and disk handling. I have added a console-callback disk driver so that Linux now runs directly off the boot/root disk. The bootstrapper no longer creates a RAMdisk image of the boot/root filesystem. This means that the root filesystem can now be any size. 6.0 DEVELOPMENT PROBLEM FOR FLOPPY DISK BOOTING SUPPORT I have discovered a development incompatibility since the last report. Currently, Linux/Alpha development is coupled with a particular console firmware that only recognizes SCSI devices and does not understand disk partitioning. The floppy drives on typical PC-class Alpha-based systems are not SCSI devices and such systems are not designed to be booted off the floppy drive. One needs to boot off a separate SCSI device and one needs some means of getting the Linux/Alpha bits to that device. How I deal with this incompatibility is determined by the particular machine I am using. My main testbed is a machine that also runs DEC OSF/1. On that machine, I use DEC OSF/1 to copy the bits to a scratch disk and then boot Linux/Alpha from that disk. I am also using a prototype machine that contains only Linux/Alpha. To move Linux/Alpha to that machine requires my writing the bits to a scratch disk on another system and then physically moving that device to the prototype, where it is booted. I'll see what I can do about alleviating this situation before releasing the SDK, but I can't promise anything. 7.0 DEVELOPERS' KIT IN THE WORKS! Now that I've gotten Linux up to a shell prompt, I'm working on packaging the developers' kit, ensuring that it works on different platforms, and ensuring that it is not TOO painful to use 8-). I'll try to alpha-test the kit on several guinea pig.... er, colleagues before turning it loose on the general public. I hope to make the kit available on several ftp sites in addition to getting it on CD in one way or another... either by minting our own one-off CDs or by piggybacking on some other FTP-archive distribution. The developer's kit will consist of: o Sources for the Linux/Alpha kernel Linux/Alpha Progress Report Page 4 o Sources for all cross-development tools (gcc, etc) o Sources for the ISP Alpha CPU simulator o Sources for whatever else has been ported in the way of libraries, utilities, etc. o Porting notes, build instructions, etc. The developer's kit will definitely work on DEC OSF/1 systems and Intel Linux systems. I will test it on whatever other UNIX configurations I can as well (e.g. Sun), and the final kit announcement will specify on which platforms it should wok. The version of Linux in the developer's kit will have only console-callback device drivers. Console-callbacks are the Alpha equivalents of BIOS calls on an Intel system. They are quite slow because they run synchronously with interrupts disabled. As on an Intel system, using console-callback or BIOS drivers will get you up and creaking, but an important item on the agenda is to write real device drivers that take full advantage of the system and the Alpha CPU. The supplied console-callback drivers will only support local disk and console character I/O. No networking, graphics, or windowing support will be available. Distributed utilities will be minimal and the kernel itself will be extremely fragile. 8.0 CALL FOR DEVELOPERS! I would like to continue the spirit of Linux as a community effort by inviting all who are interested to participate in the develoment of Linux/Alpha. Now is the time to start thinking about what YOU would like to do to help Linux/Alpha become a reality. With the release of the developers' kit, anyone with a suitable Alpha-based system will be able to contribute to the project (actually, SOME work can be done using the simulator even without an Alpha, but it will be very slow going...). At the outset, our greatest needs will be in the areas of device drivers and base system utilities. Please note that in order to do useful work in the device-driver space, you MUST have access to an Alpha system with the bus(ses) and device(s) for which you are writing drivers. Unfortunately, we are not in a position to lend out development systems at this time, except to Linus of course 8-). Anyone who is interested in participating should request membership in the linux/Alpha mailing list (see above) and let me know the particular areas in which you would like to work. I will publish the latest volunteer list periodically on the mailing list and on comp.os.linux.development so that we can avoid excessive project duplication. Linux/Alpha Progress Report Page 5 9.0 ACKNOWLEDGEMENTS Finally, I would like to publicly thank those who are making this project possible. Tops on the list, of course, is Linus Torvalds. Without him there would be no Linux for us to work on! A VERY close second are Maurice Marks and Andy Riebs, my managers at Digital Equipment Corporation. They were among the first to recognize the importance of providing a small, cheap, high-performance operating system for the Alpha family of microprocessors, and to support the Linux/Alpha project as a means of providing such an operating system. They support my efforts in numerous ways, and without them I wouldn't be sending this to you. Special thanks to Jon "Mad Dog" Hall, from the Digital Unix Marketing Group. He is a strong supporter of Linux in general and the Linux/Alpha project in particular. He provided the loaner system to Linus Torvalds. Many thanks to my project ccollaborators (so far... this list will get longer in the future!): Brian Nelson For volunteering to tear HIS hair out over the porting of libc and utilities, thus preserving my copious locks for other purposes 8-) Steve Morris For talking me throught the less-documented "gotchas" in the platform firmware, and for helping me scrounge test equipment. Charlie Greenman For applying the final spit-n-polish to these progress reports and all the other Linux/Alpha documentation. Finally, I'd like to thank YOU, the Linux community, for your outpouring of support following my initial announcement of the Alpha port. It is this support, from real live people (and potential Alpha customers! 8-) ) that helps convince management to continue supporting the Linux/Alpha project. -- Jim Paradis (para...@amt.tay1.dec.com) The purpose of time is to keep everything from happening at once. It's not working.