*** EOOH *** From NewsGroup Arms from: ast@cs.vu.nl (ANDY TANENBAUM) NewsGroups: Comp.OS.MinixSubject: Linux is Obsolete Linux technology over time Date: 29 Jan 92 12:12:50 GMTOrganization:. Fac Wiskunde & Informatica, Vrije Universiteit, AmsterdamI was in the US for a couple of weeks, so I have not commented much onLINUX (not that I would have said much had I been around), but for what it is worth I have a couple of comments now. (I have been a few weeks, yes, I have not published a comment on Linux, but the Linux value is not worth a comment, now I want to talk My view on it) AS MOST OF You KNOW, For MINIX IS A Hobby, Something That I do in Theeventing When I Get Writing Books and There no Major Wars, Revolutions, or Senate Hearings Being Televied Live ON CNN. My RealJob Is A Professor and research systems. (Most of you know, Minix is just a hobby for me, whenever I am tired of writing, and there is nothing to see on the CNN. When the show, I will continue MINIX exploration. Because I am a professor, I am a way to work is the operating system.) As a result of my occupation, I think i know a bit about where operatingare going in the next decade OR So. Two aspects standard out: (with my professional feeling, I think the future 10 In the development direction of operating systems in the year or 20 years, there are two points worthy of our attention) 1. Microkernel vs Monolithic SystemMost Older Operating Systems Aremost Older Operating Systems Are Monolithic, That IS, The Whole OperatingSystem Is A Single A.out File That Runs IN 'KERNEL Mode. 'This BinaryContains The Process Management, Memory Management, File System and Therest. Examples of Such Systems Aren, MS-DOS, VMS, MVS, OS / 360, Multics, And Many More. (1. Microconuclear mode VS single Component mode Many older operating systems are based on single component mode, that is, the entire operating system is actually just a single A.out file running in core mode, which includes process management, memory management, file system, and more. There are many of UNIX, MS-DOS, VMS, MVS, OS / 360, Multics.
The alternative is a microkernel-based system, in which most of the OSruns as separate processes, mostly outside the kernel. They communicateby message passing. The kernel's job is to handle the message passing, interrupt handling, low-level process management, and possibly The I / O.Examples of this Design Are The RC4000, AMOEBA, Chorus, Mach, And theot-Yet-released Windows / NT. (Another option is based on the microcaler's operating system, which is independent of many system services And the process outside the kernel.
Communication between processes, the role of the kernel is to manage these communications, interrupt processing, low-rise process management, perhaps I / O. Examples of this system such as RC4000, AMOEBA, Chorus, Mach, and Winnt yet issued .While I could go into a long story here about the relative merits of thetwo designs, suffice it to say that among the people who actually designoperating systems, the debate is essentially over. Microkernels have won.The only real argument for monolithic systems was performance , and thereis now enough evidence showing that microkernel systems can be just asfast as monolithic systems (eg, Rick Rashid has published papers comparingMach 3.0 to monolithic systems) that it is now all over but the shoutin`.MINIX is a microkernel-based system. The file system and memory managementare separate processes, running outside the kernel. The I / O drivers arealso separate processes (in the kernel, but only because the brain-deadnature of the Intel CPUs makes that difficult to do otherwise). LINUX isa monolithic style System. this is a giant step back Into the 1970s.that is like taking an existing, Workin, IS LIKE TAKING AN EXITING, Workin G C Program and rebrig. To me, Writing a monolithic system in 1991 is a truly poor idie. (Although I can have a long story from the advantages and disadvantages of the two, for the actual operating system People designed, the debate has ended, the microennote system is victorious! The only debate is whether the performance of a single component mode system is better, but now there is enough evidence that the microconuclear mode system can run as fast as the single component mode system (for example, Rick Rashid has published several Mach3.0 and single Component mode system comparison article). Minix is a microcaler-based operating system. File system and memory management are part of the groups other than the kernel. I / O management is also different processes (in the kernel, but this is just because the defects in Intel processor design) Linux is a single component mode operating system, which is actually retrofitting to the 70s technology, just like there will be already The workable C language program is more written in Basic language! For me, the idea of writing such an operating system in 1991 is really not good.
2. PORTABILITYOnce upon a time there was the 4004 CPU. When it grew up it became an8008. Then it underwent plastic surgery and became the 8080. It begatthe 8086, which begat the 8088, which begat the 80286, which begat the80386, which begat the 80486, and so on unto the N-th generation. Inthe meantime, RISC chips happened, and some of them are running at over100 MIPS. Speeds of 200 MIPS and more are likely in the coming years.These things are not going to suddenly vanish. What is going to happenis that they will gradually take over from the 80x86 line. They willrun old MS-DOS programs by interpreting the 80386 in software. (I evenwrote my own IBM PC simulator in C, which you can get by FTP fromftp .cs.vu.nl = 192.31.231.42 in dir minix / simulator.) I think it is agross error to design an OS for any specific architecture, since that isnot going to be around all that long.MINIX was designed to be reasonably portable , And Has Been Ported from theintel line to the 680x0 (atari, amiga, macint OSH), SPARC, AND NS32016.Linux is Tied fairly closely to the 80x86. NOT The Way to Go. (Intel's 4004CPU is beginning, then it develops to 8008, then there are 8080-> 8088 ---> 8086 --- -> 80286 ---> 80386 ---> 80486 until the nth generation. In this period, RISC technology has also been developed quickly, and some RISC processor speeds up to 100MIPS, 200MIPS or higher RISC processors. These RISC processors will not immediately disappear, but slowly replace the status of the Intel processor. Old MS-DOS programs can be run in software simulation 80386 (I write an IBM PC's simulation program with c, you can download ftp.cs.vu.nl).
