As *nixes are to the server and networking field and Windows is to the business and home market, so Macs are to the creative industries.
The life cycle of a Mac is much greater than that of a Windows computer.
I know next to nothing about Macs, so this is more a diary of what I find out, and what I need to make notes of in case I need the info again. So far I don't even know what I need to know about Macs, so I'm putting everything on this page until I know how to organise this directory. Oh, and that means that much of the following will appear in a PC-user-new-to-Macs context.
For starters - the Command key (often called Cmd has a picture of the Apple logo and a 'spinwheel' (whatever one of those is). Seems to act as the Control / Ctrl key does on PC keyboards.
The Option key has alt.written on it (I think) and the Ctrl key appears not to be like the PC Ctrl key. I have a lot to learn, obviously. The Option key can be used to write non-ASCII characters.
There is also a Power key, represented by a little left-pointing triangle (or a broken circle and a vertical line).
(the first paragraph of this could do with being moved to a more general area, as it applies to many types of computer)
The library analogy - the hard disk is the bookshelf, the books are files and the table which the lamps with green shades on in the centre of the room is the RAM. The larger the table / RAM the quicker you can work with your data, as you don't have to get up, walk over to the shelves and find your books so often. When you switch your computer off the RAM is cleared (think of it as zealous cleaners either packing or throwing everything still on the table away.
On MacOS and Mac OS X the PRAM and NVRAM are not cleared when the computer is switched off. On the desktop computer a battery keeps some settings 'alive', though on the iBook and PowerBook a capacitor keeps them alive for a limited time only (about 10 minutes). Some of the setting saved include monitor bit depth, mouse tracking, time zone, startup volume choice, speaker volume (OS X) and other settings. It appears (from this untrained eye) to be roughly analogous to BIOS settings on a PC.
To zap the PRAM (in cases of corruption), hold down Cmd, Option, p and r while starting or restarting the computer. This will reset to factory defaults.
Disk with question mark means the computer is waiting for a startup disc to be inserted, or that it doesn't recognise the internal hard drive as a startup disk.
Large X means an invalid startup disk has been ejected and a valid one needs to be inserted.
Frowning Sad Mac face means there is a problem with the computer or the system software. Older computers will indicate RAM problems with an address under the icon (indicating where the problem was found) while newer computers will play different tones for each type of problem.
Flashing globe means that the netboot server it is trying to start from is offline or doesn't exist.
Smiling Happy Mac face of grey Apple means there are no problems and it will continue to boot up.
If an application locks try pressing Cmd, Option and Esc to close the locked application only. In OX9.x and earlier click Force Quit (it won't save). In OS X a Force Quit Application dialogue will appear - choose the relevant application, then click Force Quit, Relaunch in the case of the Finder.
Presumably the major browsers for the Mac OS feature easy ways to create a desktop background from images downloaded from the web, but if not the following may be of help:
drag the image (jpg, maybe other types as well) from the browser to the desktop;
open a graphics conversion program (i.e. Graphics Converter);
convert from jpg to pict;
open the control panel, edit menu;
paste the pict file;
click in edit menu to set desktop pattern.
Runs MacOS 7.5.3 to 9.1. In addition *nix systems that can run on the PowerMac include MkLinux, LinuxPPC, PenguinPPC and ports of Mandrake 10.1.
Released between 1995-09 and 1997-02 (the 120 came out in 1997-02) and was aimed at entry-level business users.