Starting Messages When first starts up, it writes many messages to the screen which you might not be able to see. Linux maintains a special file, called /proc/kmsg, which stores all these messages for later viewing, and I've included a sample startup sequence here.   The first thing Linux does is decides what type of video card and screen you have, so it can pick a good font size. (The smaller the font, the more that can fit on the screen on any one time.) Linux may ask you if you want a special font, or it might have had a choice compiled in. In this example, the machine owner decided he wanted the standard, large font at compile time. Also, note the misspelling of the word ``color.'' Linus evidentally learned the wrong version of English.  Linux has now switched to protected mode, and the serial   driver has started to ask questions about the hardware. A driver is a part of the kernel that controls a device, usually a peripheral. Here, it found 3 serial ports. A serial port is the equivalent of a DOS  COM port, and is a device normally used with modems and mice. What it is trying to say is that serial port 0 (COM1) has an address of 0x03f8. When it interrupts the kernel, usually to say that it has data, it uses IRQ 4. An IRQ is another means of a peripheral talking to the software. Each serial port also has a controller chip. The usual one for a port to have is a 16450; other values possible are 8250 and 16550. The differences are beyond the scope of this book. Next comes the parallel port driver. A parallel port is   normally connected to a printer, and the names for the parallel ports (in ) start with lp. lp stands for Line Printer, although it could be a laser printer. That message says it has found one parallel port, and is using the standard driver for it. The Linux kernel also tells you a little about memory usage: This said that the machine had 8 megabytesmegabyte of memory. Some of this memory was reserved for the kernel--just the operating system. The rest of it could be used by programs. The other type of ``memory'' is general called a hard disk. It's like a large floppy disk permenantly in your computer--the contents stay around even when the power is off. The kernel now moves onto looking at your floppy drives. In this example, the machine has two drives. In DOS , drive ``A'' is a inch drive, and drive ``B'' is a inch drive. Linux calls drive ``A'' fd0, and drive ``B'' fd1. Now Linux moves onto less needed things, such as network cards. The following should be described in The Linux Networking Guide, and is beyond the scope of this document. The next message you normally won't see as the machine boots up. supports a FPU , a floating point unit. This is a special chip (or part of a chip, in the case of a 80486DX CPUfloating point unit) that performs arithmetic dealing with non-whole numbers. Some of these chips are bad, and when tries to identify these chips, the machine ``crashes''. That is to say, the machine stops functioning. If this happens, you'll see:   Otherwise, you'll see: if you're using a 486DX. If you are using a 386 with a 387, you'll see: If you don't have any type of math coprocessor at all, you'll see: The kernel also scans for any hard disks you might have. If it finds any (and it should) it'll look at what partitions you have on them. A partition is a logical separation on a drive that is used to keep operating systems from interfering with each other. In this example, the computer had one hard disk (hda) with four partitions.  Finally, mounts  the root partition. The root partition is the disk partition where the operating system resides.  When ``mounts'' this partition, it is making the partition available for use by the user.

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