Newsgroups: comp.os.minix,news.answers,comp.answers Subject: MINIX Frequently Asked Questions (Last Changed: 1 January 1996) From: glen@winternet.com (Glen Overby) Reply-To: glen@winternetcom (Glen Overby) Followup-To: comp.os.minix Distribution: world Organization: $HOMEs for wayward hackers Keywords: info answers Summary: Commonly Asked Questions -- With answers! Approved: news-answers-request@mit.edu Archive-name: minix-faq Version: $Id: minix-faq,v 1.15 1995/03/03 17:17:35 overby Exp overby $ If you have questions and answers to contribute to this FAQ sheet, please send them to me, glen@winternet.com. I'm looking for contributions to this FAQ, not for questions to be answered privately. FREQUENTLY ASKED QUESTIONS ON COMP.OS.MINIX This Frequently Asked Questions (FAQ) list is intended to accompany the Minix Information Sheet. Some of the information here is duplicated from the Information Sheet when deemed appropriate. In creating this, I have attempted to recall the Great Questions (and their answers) as well as the Great Discussions from the net. Many thanks to everyone who has contributed to this document. Several things to remember when you ask questions on the net: Please supply enough information for people to actually help you. Things like what Minix version, your hardware configuration, and so-on are almost always necessary to not have to take shots in the dark. If you are reluctant to tell any or all of this, don't expect a good answer. There are some questions for which there is no answer, because nobody has encountered the problem previously or there is no good solution to the problem. 1. WHERE CAN I GET MINIX? Minix 1.7 is distributed for free on the Interenet. See Andrew Tanenbaum's minix web page page 2. WHAT VERSIONS OF MINIX EXIST? There are two releases of Minix currently in wide distribution: + Minix 1.5, distributed commercially by Prentice-Hall Available for: IBM PC clones, Apple Macintosh (680x0), Atari ST, Commodore Amiga, Sun SparcStation. + Minix 1.7 distributed freely on the Internet Available for: IBM PC clones. 3. HOW DOES PDP 11/44 MEMORY MANAGEMENT WORK? This was the first big off-the-topic discussion on the group, and it's still not an appropriate topic, so if you are still intrigued about pdp-11 memory management, consult the DEC processor handbooks, your local DEC historian, a newsgroup on that topic such as alt.sys.pdp11 or some harmless newsgroup like alt.dev.null. 4. PLEASE SUBSCRIBE ME TO THE MAILING LIST Please don't ask 26,000 people on the newsgroup to do that, since you can ask a computer to do it for you! If you are on the Internet, or can send email to the Internet, then you can get this newsgroup via a mailing list, MINIX-L (aka info-minix). To subscribe to the list, send a message to listserv@vm1.nodak.edu (internet) or listserv@ndsuvm1 (bitnet) saying: signup minix-l your_full_name If you have trouble, contact the listserv maintainer at postmaster@vm1.nodak.edu Al: please give me an update on this 5. PLEASE UNSUBSCRIBE ME FROM THE MAILING LIST Use the same procedure as for subscribing, but use "unsubscribe" in- stead of "signup". 6. WHAT IS THE ROOT PASSWORD? It's in the book, on pages 373 (login "ast") and 380 (login "root"). If you didn't buy the book, that's only the start of your problems. 7. MINIX DOESN'T WORK WITH MY HARD DISK. Is this still applicable? There are many potential sources of this. Several are: You are running an RLL controller on an XT. You must change "NR_SECTORS" in the configuration file, from 17 (standard for MFM controllers) to 25 (Adaptec controllers) or 26 (Western Digital and others). 8. THE SINGLE THREADED FILESYSTEM IS A REAL BOTTLENCK. True. It's only noticeable when you are running massive background processes, or putting multiple users on your computer. This "problem" has been recently "fixed" and the "solution" posted to the net. See your nearby bit-bucket (archive site) for it! You've got the source. Fix it. 9. IS THERE X-WINDOWS FOR MINIX? Not for standard Minix. It would be difficult if not impossible (that was meant as a challenge!) to put X on Minix because X is huge. Unless you have many megabytes of memory, it would be impossible to run X clients and servers on one machine. It will also certainly require 32-bit mode operation. Minix-386vm, however, does support X11R5 (see question 11). Don't be fooled by Mini-X. This is just an EGA- or VGA-graphics driver and a windowing library for Minix-PC. The API is similar to X11 (but not identical), so porting X programs might be easy. It is not possible to run several programs using it at once, however. There is also a port of MGR, but I don't know about its current status. Is this still correct? 10. DOES MINIX SUPPORT TCP/IP AND NFS Yes, Minix supports TCP/IP. However, you must build a new kernel -- the distributed one does not have TCP/IP built in. There is no NFS for Minix.a 11. WHAT IS THE DIFFERENCE BETWEEN THE 80386 AND THE 386sx? There is no difference between 386sx/386dx except for the bus (24-bit addresses and 16-bit data). 12. WHAT ARE THE MINIMUM HARDWARE REQUIREMENTS FOR MINIX? check the docs on this one Theoretically you can run it on an XT with 512kB RAM and 2 floppies. Unless you are particularly fond of juggling disks, you would want at least 20MB on a hard disk, though. A 286 will give you memory protection and the ability to use more the 640k of memory. 2MB are recommended. If you have a 386 and decide to use one of the 32-bit kernels, you should have at least 4MB RAM. For Minix-386vm 60MB of hard disk are probably the minimum, if you want to keep the sources online. For the i386 Minix, you need at least two megabytes of RAM 13. How does vol work? 14. Can I run a networked XT? 15. How do I use the boot monitor? 16. How do I change the size of the RAM disk? First, let's discuss the default size of the RAM disk. This is the size of the root file system on the boot device. This is 200K for the TINYROOT boot floppy, or 600K for the standard ROOT boot floppy. So, in the first place, when you are starting Minix for the first time you should use the TINYROOT file system if you have a machine with only 640K or 1M memory. If you use the instdist script to install on a hard disk the boot device file system will be 720K for 16 bit (i86) Minix or 1024K for 32 bit (i386) Minix. (Note that instdist makes a 1.44M partition for the root, but the file system it puts on the partition doesn't use the entire partition). If you want to continue to use a RAM disk after you have installed to the hard disk, but you want its size to be smaller than the default 720K or 1024K, you will have to use mkfs to make a new file system of the desired size on the root subpartition and then copy the files you want on your root device, reinstall the bootblock, etc. The usage.8 man page and the text of instdist itself provide information on how to do a manual installation. There are several other possible manipulations of the RAM disk. 1. You can have no RAM disk at all. 2. You can put your root file system on a RAM disk that is larger than the device where the root files are stored permanently. 3. You may want a RAM disk that is not your root device. No RAM disk: In the boot monitor (which you enter by pressing ESC when you see the "Press = to start Minix" prompt), enter "rootdev=bootdev". Type "set" to verify the boot parameter settings and type "save" if you want to make this a permanent change, and then type "main" or "menu" to continue booting. On a small system this will allow you to use all of memory for programs, at the price of slower access to the root file system. Most hard disks are fast enough that a RAM disk isn't really needed. You may get more of an effective speedup by recompiling Minix and using more memory for buffers, anyway. Root on a RAM disk larger than the boot device: In Minix 1.7 you can change the size of the RAM disk from the boot monitor prompt. By default the ramsize parameter is initially set to zero, and the RAM disk takes the size of the file system that is copied to it. You can change ramsize to any size up to 8192K by changing the ramsize parameter (for example, "ramsize=4096"). Of course, the RAM disk can't be smaller than the boot device that will be copied to it. RAM disk not used as root device: In Minix 1.7 you can also create a RAM disk that is not used for the root. This is more complicated than the other options. In the boot monitor set "rootdev=bootdev" so the root image will not be copied to the RAM disk. Then use the ramsize parameter to specify the desired size of RAM disk. This will create an empty RAM disk without any file system at boot time. Once Minix has started you can use mkfs to create a file system and then mount /dev/ram. If you have a reason to do this regularly you could put the mkfs and mount commands in your /etc/rc file. _________________________________________________________________ CONTRIBUTORS Thanks to the following people for contributing to this FAQ: Albert S Woodhull <aswNS@hamp.hampshire.edu> _________________________________________________________________ Glen Overby (glen@winternet.com) (overby@rrnet.com) Last modified: January 16, 1996