The Linux/MIPS FAQ Contents: What is "Linux/MIPS"? On what hardware will it run? Is Linux/MIPS little or big endian? Is Linux/MIPS a 64 bit OS? Will it run on Multiprocessor machines? What is the state of the project? Any support/development tools available? Is there a mailing list? Can I help? What does it cost? Q) What is "Linux/MIPS"? Linux/MIPS is a port of the LINUX Operating System to computers equipped with MIPS processors. Linux/MIPS is based on the latest sources distributed by Linus Torvalds, the author of the original Linux/i386 kernel. Q) On what hardware will it run? Linux/MIPS will run on most ARC (ARC = Advanced Risc Computing) compliant systems equipped with Mips R4x00 processors. A port to older MIPS microprocessors is now in progress. Ports to the following systems are in progress: Acer PICA-61 (R4400, 134/150 MHz CPU clock, up to 2 MB L2 cache, on-board video, SCSI, ethernet and serial/parallel I/O plus 5 free ISA slots) DECStation 5000/2x, 5000/100, 3100, and others. (a.k.a. PMAX, all R3000 based) Deskstation rPC44 (R4400 100 MHz CPU clock, up to 2 MB L2 cache, 5 free EISA slots) Mips Magnum 4000PC (R4000, 100 MHz CPU clock, on-board video, SCSI, ethernet and serial/parallel I/O plus 4 free EISA slots) Olivetti M700-10 (R4000, 100 MHz CPU clock, on-board video, SCSI, ethernet and serial/parallel I/O plus 4 free EISA slots) The ports to following systems are idle because of hardware and/or documentation problems: Deskstation Tyne (R4600, 134 MHz CPU clock, up to 2 MB L2 cache, 2 free VLB and 4 free ISA slots) In the meantime many other platforms turned out to be good candidates for Linux/MIPS. Although we don't have code for Mips platforms other than the systems listed above, chances are quite good that some of the following systems will be supported in future: Siemens/Nixdorf RM200/RM300/RM400 series. ShaBLAMM's NitroVLB cards SGI's UltraP Pentium-replacement board NEC RiscStation and RiscServer machines All other ARC (ARC = Advanced Risc Computing) compliant Mips machines, even those we don't know yet Mips RC3xxx and Magnum 3000 Sony News (with R3000 cpu) Q) What is the current status of Linux/MIPS? The kernel is quite reliable and supports ext2fs and NFS filesystems. Other filesystems should also be working but are untested. Supported peripherals can be divided up in four groups: Polled I/O via ports. The only networking driver that has been tested is the NE2000 which works flawless as expected. Other ISA/EISA cards that use I/O port polling like IDE should also be working. Shared memory cards. These definately don't work yet; I'll need to do a little fix on the kernel for them and many drivers on them. DMA cards. These will definately still need some work. Onboard drivers. For Acer Pica, Magnum 4000 and Olivetti boards there are currently no drivers available for the onboard peripherals except for the floppy driver. Since these missing driver will still have to be written, ISA/EISA peripherals that are left from some old PC are a good workaround for now. Q) Is Linux/MIPS little or big endian? At least all of the ports to ARC systems will be little endian. However, it might be necessary to run older Mips systems, such as the Sony News and Mips RC3xxx, in big endian mode. If and how we can provide user code compatibility thru the whole Mips line hasn't been decided yet. Q) Is Linux/MIPS a 64 bit OS? Not yet. This has multiple reasons: The older members of the R-family are only 32-bit processors. Keeping Linux/MIPS a 32-bit only operating system helps to make the R3000 port much easier. At the time when the Linux/MIPS project started the Linux sources weren't 64-bit clean. GCC and Binutils still don't support 64-bit code perfectly. 64-bit code is bigger than 32-bit code since it doubles the size of some C data types. As a result not only more resources are being used by 64-bit code - the increased size of code and data even reduces cache hit rate and therefore overall performance. There are of course applications that take advantage of 64-bit processing. These are however not the usual stuff that is being used for Linux. The upward compatibility of the R-series microprocessors provides an easy way to switch to true 64-bit processing without breaking compatibility. 64-bit Unices aren't yet really standardized. Especially IRIX6 which will probably the guidline for a future 64-bit Linux/MIPS wasn't yet released when the Linux/MIPS project started. Q) Will it run on Multiprocessor machines? The current kernel doesn't contain very much of the special SMP stuff that is required. It will therefore only make use of one processor. Nevertheless there is SMP support for Linux/i386. Q) What is the state of the project? We have a bootstrap loader which should run on most ARC systems. A network bootloader for DECstations using the MOP protocol is almost complete. The current kernels based on Linux 1.3.57 include drivers for console, keyboard and ethernet. SCSI will be available soon. On the Acer, Olivetti and Mips boxes, the kernel boots from a floppy, and then mounts root from a NFS server. The kernel is quite reliable; my own machine has currently an uptime of over five days. The only thing that will prevent it from running longer is the fact that kernel hackers frequently reboot their machines. A network bootloader for R3000-based DECStations using the MOP protocol is almost complete, though certain models of DECStation may be booted using tftp/bootp. Both R3000 and DECStation specific code has been written for the 1.2.11 kernel, and will be released as patches to the current 1.3.57 kernel soon. An experimental DECStation kernel image is already available. This ought to boot to the point of showing the "Calibrating delay loop..." message on most DECStations based on R3000 CPU's. On the Linux/MIPS FTP sites is a better than nothing distribution available. It currently just a bunch of thrown-together programs and will somewhen later be replaced by a real distribution. Q) Any support/development tools available? Yes. We have cross compilers, assemblers and linkers ready to use for Linux/i386, SunOS 4.1.3 and Solaris 2.3. A Mips R2000/R3000 simulator (SPIM) for Linux/i386 is also ready to download. Binaries and documentation are available from the Linux/MIPS FTP sites. The current version are gcc 2.7.2 and binutils 2.6. There are patches required to both of these packages in the "src" subdirectory in the above locations. Both GCC and Binutils may be configured in four target flavours. This may be a bit confusing but is necessary since Linux/MIPS is currently migrating from a.out to ELF object format and is available for both big and little endian byte-order. The four system flavours are: mips-linux - big endian a.out. mips-linuxelf - big endian ELF mipsel-linux - little endian a.out mipsel-linuxelf - little endian ELF For ease of installation binaries for Linux/i386 hosts are also available. Native binaries for Linux/MIPS are included in root-0.00.tar.gz Linux/MIPS FTP sites This is a very incomplete list of Linux/MIPS sites. There are more available and you should try always to use the nearest site. sunsite.unc.edu:/pub/Linux/ALPHA/mips ftp.mcc.ac.uk:/pub/linux/MIPS ftp.ibp.fr:/pub/linux/mips ftp.uni-mainz.de:/pub/Linux/arch/mips ftp.fnet.fr:/linux-mips ftp.softway.com.au:/pub/linux-mips. This site only carries the developers latest DECstation stuff. Q) Is there a mailing list? Yes, it is linux-mips@vger.rutgers.edu. To subscribe to this list, send a message to Majordomo@vger.rutgers.edu with the command "subscribe linux-mips _your_email_address_" in the message body. However this list is more or less dead since most people discussing Linux/MIPS are developers subscribed to another list.Please contact linux-mips@fnet.fr for further information. Q) Why should you use Linux/MIPS? Just a few of the reasons that come to mind: The manufacturer does no longer support your old operating system Your old operating system is buggy and drives you crazy. Your machine's native OS is Windows NT but UNIX is your favourite flavour of operating system. Linux is free. You always liked Linux You want to revive a box that is catching dust Hacking kernels is what you call fun You're developing a new computer or an embedded system that needs an operating system. Q) Can I help? Sure! If you have a Mips box, please let us know. Eventually we find a way to include your box in the target list. And we would of course appreciate it, if you can spend some time into hacking kernel and/or user code. Please feel free to contact us at linux-mips@fnet.fr! Q) What does it cost? Nothing, since Linux/MIPS is freely available. But the development costs -- as any development. We would appreciate any donations such as: FTP Mirror Sites (please contact linux-mips-ftp@fnet.fr) People doing real work Hardware (unused boards, disks etc.) Documentation about hardware details Last changed 26-Jan-1996 Luc.Beurton@fnet.fr