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Internal components of a Macintosh (or a PC) Classification: Mother board The RAM Storage memories The hard disks Power The video board The mother board: This is the core of the machine: all the internal devices (RAM, hard disks,... ) are connected and driven by the mother board. The components of this card which drive the devices are called "the controllers". If the mother board can show extensions possibilities (like slots for more RAM for instance), it is also the area in which all the information circulates at a specific speed: the clock frequency (Mhz) of the board. So no need to add an external high-speed video acquisition card if the heart of your machine is slower than the speed of this card! So, this card really defines the power of the machine. A example of a mother board. The cooling fan. Slots for RAM. AGP video card. Backup battery (time, localization, screen resolution..) and just next, on the right, the reset switch of the mother board. IDE ribbon for connecting the hard drive(s). Power connector. PCI SCSI additional card. Airport card slot. The mother board. RAM slots. Different heights for RAM. The closest slot is empty. The fan cooling the cpu (which is just under the fan..of course). The AGP video card. The fan cooling the mother board. An internal Firewire port. The RAM The RAM is used to load the system: printer driver, network services, ... Current running applications and current opened documents are also located in the RAM. This is a quick access memory but a vanishing one: when the machine is powered off, the data in RAM are lost. -> it is important to regularly save opened documents. This RAM can be compared to the following human behavior. If your colleague just cry "Dan, call back Nick at 02-877", you certainly keep this number into your memory until you physically call Nick. If Nick's phone is busy and if you do not have a "redial" option, you still keep the number into your memory until you have a better opportunity to call him again. But if the this number is not the Nick's one, I guess you certainly write down on a Post-It something like "Find Nick's number and call him". This Post-It note is what I call the Storage Memory. Ci-dessus plusieurs barrettes, celles de gauche sont sorties d'un G4/400 et celle de droite (une 128 mégas) d'un ibook G3 600 MHz. La mémoire pour portable est, comme on peut le voir, beaucoup plus petite et de ce fait, beaucoup plus chère. Storage memory In this kind of memory, we store all the things we want to keep. We speak now about hard disks, but in the past such memory was made of floppies. So, on the disk, we find all the content of the machine: the system, the applications we use, the documents we create, the music we listen to,.. More and more the operating system requires a huge amount of RAM to operate. If it is short of RAM, it will uses a portion of the hard disk as a memory for running: this is the swap space. This space is taken over the available capacity of the hard disk but, as on disk, it is slower than true RAM (RAM is 3000 times faster than the swap space). The more the system allocates swap space, the slower it runs. -> It is important to close all the applications we do not use. The hard disks On the left a 3,5''. On the left a 2,5 '' 9.5 mm thick for portable machines. Classification on Macs. They wer first SCSI: easy to install, can chain 7 drives on the same cable: each compoponent of the chain will receive an unique ID and the only difficulty was to be sure that no two same IDs were present on the chain. From the original SCSI (SCSI 1) 5 Mo/s standard, we have: Ultra SCSI (SCSI 2) 20 Mo/s Wide Ultra SCSI (SCSI 3) 40 Mo/s Wide Ultra SCSI 2 80 Mo/s Wide Ultra 160 (Ultra 3 SCSI or SCSI 5) 160 Mo/s Wide Ultra 320 SCSI 320 Mo/s On the Macs we have SCSI 1 until the arrival of Ultra IDE (from the PCs): less expensive. Some Macs received SCSI 2 cards (BW G3 for instance). -> The IDE standard arrives on the Performas et LC 630 machines. The last ones (Low Cost !) used an IDE hard disk, less expensive, but still had an external SCSI connector ! And the most funny: all the Macs with a true IDE controller were buggy: they only can handle one peripheral on the chain !. The IDE standard evolution steps: Standard IDE: 16 Mo/s max 540 MB -> no CD drive allowed in the chain. EIDE (or Ultra IDE) enhanced IDE interface: 4 units, 8,4 Go and the optical drive ! And this Ultra IDE arrives on the Mac plateform Ultra DMA-33 (also called Ultra ATA/ ATA 4) = 33 Mo/s. -> max 32 Go Ultra DMA-66 (also called Ultra ATA 66 )= 66 Mo/s max 128 Go Ultra ATA/100 and ultra ATA/133 And now Serial ATA (S-ATA) on G5= 150 Mo/s; 1 disk per controller. Hot pluggable. Note: on an EIDE controller, two peripherals only (one is called the "master", the other one the "slave"). The power That's the big stuff which transforms the 220V tension into 5 and 12 V required by the machine's components.   La carte graphique This card computes all the things to be drawn on the screen. The card contains a dedicated CPU which helps the main CPU of the machine when drawings are required. That's why, on some machines (like the pismo powerbook G3 400 MHz), one can simultaneously displays data on two screens. The video card also have a specific RAM for speeding up performances: 8 MB in the past, now 32/64 or 128 MB. On the first Macs, the video card were integrated to the machine. Then we have the opportuniy to add a video card (Nubus slot): this second card were used to handle another screen, doubling therefore the available desktop area... for instance on the quadra 650 :-) -> The next, video cards were based on PCI connector (picture above). Then, with an AGP connector (picture below) with two connectors: one VGA and one DVI. We have now the AGP 2x / 4x et 8x... the last one being incompatible with the previous ones :-(