A very brief look at some typical expansion cards now follows. The first of these is shown at Fig. 4.15: an ASUS EAX1300PRO graphics card.
One point is particularly noteworthy with respect to this example. Although not obvious at first sight, this is a PCI Express card and not a PCI card. The clues are in the positioning of the space between the two sets of contacts on the connector and in the tail on the right-hand side of the connector, just under the centre of the fan. Ordinary PCI cards do not have tails, and it is this tail, trapped by the retention mechanism on the PCI Express x16 socket on the motherboard, that locks the card in place, a feature that has been found necessary for graphics cards. Although a similar retention system is used with the older AGP sockets, the positioning of the space between the two sets of contacts is different between the AGP cards and the PCI Express x16 cards. Close examination of the PCI and PCI Express x16 sockets in Fig. 4.7 shows that these
too have different spaces between the two sets of contacts, and this spacing can be used to aid identification of the different expansion cards.
At Fig. 4.16 we have shown an old AWE32 Sound Blaster card. Although these are now obsolete, as we would expect audio to be implemented directly on the mother- board these days, we have shown this card for two main reasons.
First of all it is a good example of a 16 bit ISA card, and this can be recognized by the position of the split between the two sets of contacts seen at the bottom of the figure. Also just visible on the right-hand side of the figure is the metal plate, which forms part of the outer casing, and a number of sockets through which various sound connections can be made. The second reason for showing this card is that this model, in common with many sound cards that were manufactured before the IDE CD-ROM drive interface had been developed, has three different CD-ROM interface sockets on the left-hand side of the figure. These enable a CD-ROM drive to be fitted which interfaces through the Sound Blaster card, the technique that was most frequently used on older systems to provide a CD-ROM facility.
The final picture, at Fig. 4.17, is that of a simple network card. Again, this has a PCI connection, shown at the bottom of the picture, and we can just see a network cable plugged into a 10BaseT socket on the left-hand side of card.
Fig. 4.16 AWE32 Sound Blasfer card (photograph: Tony Sammes and Brian Jenkinson).
Although there are very many different kinds of expansion card, these three examples should give a reasonable view of what to expect inside the box. Often the purpose of an expansion card becomes evident from the connections that are made to it. Equally often, there is useful information screen printed on the printed circuit board which will help identify the manufacturer of the card and its type.
References
Adams, C. K. (1981)Master Handbook of Microprocessor Chips, Tab Books Inc., New York. Apple Computer Inc. (2006)Device Drivers FireWire. URL:http://developer.apple.com/
hardwaredrivers/fireWire/Index.html.
ASUS (2005) ASUS Motherboard A8N32-SLI, E2280, Second Edition V2, October 2005, ASUSTeK Computer Inc.
Freer, J. (1987)Systems Design with Advanced Microprocessors, Pitman, London.
IBM (1996a)Understanding DRAM Operation, IBM Applications Note, 12/96, International Business Machines Corp. URL:http://www.cs.albany.edu/~sdc/CSI404/dramop.pdf. IBM (1996b) Synchronous DRAMs: the DRAM of the future,IBM MicroNews, First Quarter,
4–6.
IBM (1996c)Understanding VRAM and SGRAM Operation, IBM Applications Note, 12/96, International Business Machines Corp. URL:http://www.ee.surrey.ac.uk/Personal/ R.Webb/l3a15/extras/vrmsgrm.pdf.
IBM (1997)Understanding Static RAM Operation, IBM Applications Note, 03/97, International Business Machines Corp. URL: http://www.ee.surrey.ac.uk/Personal/R.Webb/ l3a15/extras/sramop.pdf.
IBM (undated)Understanding EDO (Hyper Page Mode), IBM Applications Note, International Business Machines Corp. URL:http://www.chips.ibm.com/(no longer available). Intel (1979)The 8086 Family User’s Manual, Intel Corporation.
Khambata, A. J. (1982)Microprocessors/Microcomputers Architecture, Software, and Systems, John Wiley & Sons, New York.
Mueller, S. (1998)Upgrading and Repairing PCs, 8th edn, Macmillan Computer Publishing, New York.
Peacock, C. (2005)USB in a Nutshell, Making Sense of the USB Standard,15 June 2005. URL: http://www.beyondlogic.org/usbnutshell/usb1.htm.
USB (2000)Universal Serial Bus Specification Revision 2.0, Compaq, Hewlett-Packard, Intel, Lucent, Microsoft, NEC, Philips, 27 April 2000. URL:http://www.usb.org/developers/ docs/usb_20_05122006.zip.
5.
Disk Geometry
Introduction
In this chapter we look in detail at the geometry of floppy and hard disk drives to find out exactly how information is stored and how it might be hidden. The topics we are going to consider are the following:
● The development of the hard disk
● Physical construction – heads, tracks and cylinders ● Formation of addressable elements
● Encoding methods and formats for floppy disks ● Encoding methods and formats for hard disks ● The formatting process
● Hard disk interfaces
● IDE/ATA problems and workarounds ● The boot sequence and POST
● The master boot record and partitions ● Directories and file systems
● Hiding information