The Real Truth About Micoshaft 1176

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In comp.os.linux.advocacy, Michael Trausch wrote on Sat, 15 Apr 2006 16:42:37 -0400

Define "fully functional". There is a *large* contingent of issues within that statement.

I will now go into some detail as to the problems with Linux qua Linux, to illustrate some of these issues.

1 Linux is a kernel. In fact, Linux is a piggybacked kernel, if one can use that term; the kernel is built into vmlinux then compressed and shoved into something called "piggy.c", which I'd have to look at, but it's clear to anyone who's ever tried 'make vmlinuz'. By itself, it just sort of sits there, although one can attempt to boot from a floppy if one hasn't crammed too much on the kernel. This sort of thing was and still is commonly done in Windows programs -- though for a slightly different purpose (self-extractors). Not all that new but it is useful. Of course few boot from floppy except in emergencies.

2 Linux+GRUB is a somewhat useful combination (Linux+LILO and Linux+LOADLIN work equally well here too). Too bad it won't boot all the way; Linux will look for various files on the hard drive (if it can find the hard drive -- a driver problem -- parbreastions on the hard drive -- a compatibility problem, under certain circumstances on non-x86 hardware -- or understand the filesystem format, which could be an issue if someone forgot to include reiser in the base kernel instead of loading it in a module later. if need be.) But at a certain critical point, in main.c, Linux looks for init in various places, then looks for bash. If it finds neither, it panics. (An init= override is available, for specialized applications. In GRUB, hit 'e' then just type it in. In LILO, one can add it to the command line. In LOADLIN, one can presumably include it after the linux kernel proper; I'd have to look.)

3 Congratulations! It's found init. Erm...how does one log in? PAM, some variant of getty, andbin-login, probably, along with a few other files. I'd have to look. Editing can be done with vi or emacs -- buttuming emacs is smart enough not to try to open the display; there are several variants. Bash now presents its '$' prompt, unless one is doing root stuff ('#') or the user's done some customization work.

4 Graphics? What graphics? Oh, you need X. Not that X by itself will do all that much; the stipple screen isn't all that pretty and the apps are xterm, xeyes, xev, and xedit; there's a few others but I'd have to look, and they're all fairly basic stuff. On Gentoo the X source is split into several parts so one can e.g. install X without any of these, but in a stock X install one gets the lot. Of these xterm and xedit are arguably the most useful. Oops, can't move 'em.

5 Window managers. There's a number of them; twm is extremely crude by today's standards (no reparenting) but might be good for coders to illustrate some of the basics. There's a fair number of others, some very esoteric.

6 Most people will install KDE (including Qt) or Gnome (Gtk). These are desktop environments, and are chock full of useful utilities of their own. And yes, these include window managers, but the Qt and Gtk widget sets allow construction of full-blown applications. Or one can use Java, which works at the X (4) level and below.

7 Additional software includes such things as OpenOffice and Koffice, Gnumeric, Epiphany-Mozilla-Firefox, and xemacs.

8 I should also mention that X provides network transparency. For those of us with multiple machines that's a bit of a treat, although VNC on Windows serves much the same purpose, and might be more efficient. However, VNC does not (yet?) have the capability of allowing machine A to open windows onto machine B's desktop; VNC simply shows machine A's desktop. (An equivalent is to open an XNest on machine B and then start gnome-session on machine A, pointing to the correct display. Audio and GL won't work but most other things should at least attempt to function.) Nor is it clear whether VNC encrypts its event-drawing traffic. With ssh, one is buttured of encryption unless one explicitly says "no", though one can also tunnel VNC through SSH.

It's a very interesting layer cake (with lots of files to help one break out of one's doldrums :-) ), and one can at least identify the layers without too much trouble. (Windows has similar layering but it's far murkier in there.) One Linux advantage of course is that most baselevel utilities will not care whether X is running or not. cp, ifconfig, rm, mv, ls, df, vi, and ghostscript won't care if X is there or not (although ghostscript can take advantage of it).

So...where is the GUI mandatory? Depends on what one is doing.

Is the CLI mandatory? I'm not sure. Most Linux installs include a terminal emulator (xterm, gnome-terminal, kterm, etc.); these basically open a window and create a process, and one can then talk to that process on a keystroke-by-keystroke basis, using what is known as a 'pseudo-tty'. The real 'tty' refers to a teletype, and is a Unix archaism; nowadays one either uses the term 'COM' port, RS-232, or serial line. In many Unixes drivers are also included for keyboard and a text screen, which Linux users can access using ALT-F1 or CONTROL-ALT-F1; these act very much like old-style addressible "glbutt tube" terminals, and if one has framebuffer enabled one can even draw things without X (ggi-kgi and zgv are the only things I know of that take advantage). Many systems will also support CONTROL-ALT-F2 through ALT-F6 as well, and each one can be individually logged into. The X server is typically on ALT-F7.

But if one just wants to do the clicky thingy, Gnome in particular allows for a fair amount of configuration for the user's desktop by pulling down utility menus. I don't think Gentoo has stuff for configuration of the system using nothing but menus and requesters, if one is running as root, but would have to look, and in any event one can edit config files using a fair number of provided editors -- vi and emacs, but also gedit, kedit, and even xedit, if one can stand its 80's era scrollbar interface (Xaw3d helps there, though).

HTH.

-- Windows Vista. Because everyone wants a really slick-looking 8-sided wheel.