Macintosh - What's Inside

Processor Chip	the brains of the a computer, where the computer actually makes its calculations. Its also called the processor, the microprocessor, or the CPU (for central processing unit ). Be ware that the term CPU is sometimes also used to refer to the Mac itself, as distinct from the keyboard, mouse, external monitor, etc. Older Macs use Motorola processors - the 68000, 68020, 68030, 68040, and the Power Macintosh use 601, 603, and 604 chips. The higher the number, the more advanced the chips capabilities. 68000   Mac Plus, SE, Classic 68020   Mac II, LC 68030   SE/30, IIcx, IIfx, IIsi, IIci, Classic II, LC II 68040   Centris 650, Quadra Family, Some Performas
Coprocessor	A coprocessor is a second chip that specializes in math, graphics or some other kind of special computation. When the processor receives the kind of job the coprocessor specializes in, it hands off the job to the coprocessor, which takes care of it faster than the processor could and then sends back the answer. PMMU (paged memory management unit ) is a special kind of coprocessor that helps manage memory efficiently
Clock Speed	The operations of the processor chip are synchronized to pulses generated by a vibrating quartz crystal. The frequency of these pulses is called the computer's clock speed and is measured in megahertz - millions of cycles per second (abbreviated MHz ) . The higher the clock speed the faster the processor is. You should also be aware that clock speed alone won't tell you how fast a computer is. The 68030 chip not only thinks faster, it also moves twice as much data at a time, in 32-bit instead of 16-bit chunks. The PMMU chip built into the 68030 speeds things up to.
ROM	Read-only-memory. Its information that's built into the computer and doesn't need to be loaded from the disk.. An increase in ROM size (from 512K to IMB, say) makes the Mac smarter and capable of doing more things (or able to do the same things faster).
RAM	Random-access memory. Its more meaningful to think of RAM as read/write memory - memory you can both write data into and read data out of. A computer's RAM is the working space in which you create and modify documents and do other work. Most RAM is volatile , which means the information stored in it is lost each time you turn power off. Because all programs work at least partially in RAM, how much RAM a Mac has affects not only how fast it functions but also how many applications you can have open at one time, how big a document you can work on, etc. RAM chips usually come packaged in SIMMs, single in-line memory modules. A Mac's RAM maximum depends upon what kind if SIMMs it can use and how many SIMM sockets it has. Manufacturer's keep cramming more and more RAM onto memory chips, making them denser and denser. Currently you can have as much as 128MB RAM on a single SIMM.
Expansion Slots	Fittings that let you add cards inside the Mac that do special tasks, like accelerate your computer, run a large monitor, or give you Ethernet access. There are two kinds of slots, Processor Direct Slots (PDSs) and Nubus Slots PDSs connect the card plugged into it directly to the CPU, which makes the card fast. A Mac can only have one PDS; the SE/30, Portables, LCs, IIsi and all the Quadras and Power Macs have them. PDSs in different models are generally incompatible, which is why their are far fewer PDS cards than You can put a NuBus Card into any NuBus Slot you want, and the cards do not have to fight over which has priority. In addition to these two basic kinds of slots, various Macs contain special sorts of slots for extra memory (SIMM Slots), cache cards, modems, etc.
Sound	All Macs have a Sound Output (mono for oldest Macs like the Plus and LC, Stereo for newer Macs like the Quadras). Newer Macs also come with the ability to record sounds (Sound Input) - these computers come with a microphone.
Built-in Video	Means you can plug a monitor into the Mac without having to install a video card. The si, the LCs, and the Quadras use separate VRAM (video ram ), but the ci uses its own regular RAM, which means hooking a monitor to it without a video card tends to slow down the ci's other operations.
PRAM	Parameter RAM - keeps track of such parameters as date, time, various other control panel settings. It also remembers what's connected to the printer and modem ports on the back of your computer. A battery provides power to the PRAM. Sometimes the information in the PRAM gets corrupted. In this case you can reset it to its original defaults, an action called Zapping the PRAM. In System 7, you hold down the option+command (apple)+ P + R keys simultaneously and select restart from the special menu . There's no alert; everything happens invisibly. Sometime the battery powering the PRAM dies and needs to be replaced. You can tell that this is the case, if you have your parameters (e.g. date, time settings) get reset every time you power down your Mac.