With a dot matrix printer, light then dark print is most commonly caused by:
Answer: B
Correct answer: Erratic ribbon advancement
If the ribbon does not advance evenly, some characters are struck through fresh ink and others through a used part of it, so the print alternates light and dark down the page.
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How many DMA channels are there in an AT class PC?
Answer: D
Correct answer: 8
An AT class PC has two cascaded DMA controllers giving eight channels, 0 to 7. Channel 4 is used for the cascade itself, so seven are available to devices.
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Which port is most commonly used to connect a modern monitor carrying both video and audio?
Answer: D
Correct answer: HDMI
HDMI - High-Definition Multimedia Interface - carries uncompressed digital video and audio over a single cable and is the usual connection for monitors and televisions. DisplayPort is the other modern standard, and USB-C can carry a DisplayPort signal too. The other three are legacy interfaces, and knowing what each did is worth a little effort. The PS/2 port connected keyboards and mice, colour-coded purple and green, and was superseded by USB. The parallel port, with 25 pins, connected printers and sent eight bits at a time down separate wires. The serial port, with 9 pins, sent one bit at a time and connected modems and mice. Parallel transmission was faster at short distances but suffered from timing skew between the wires as speeds rose, which is why every modern high-speed interface - USB, SATA, PCI Express, HDMI - is serial. VGA is the older analogue video connector, still found but now rare.
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Every video card must have?
Answer: B
Correct answer: RAM
A video card must hold the image it is displaying, so it needs memory - the frame buffer, read out sixty or more times a second to refresh the screen. A processor of its own is optional; RAM is not.
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What is the jumper setting on a SCSI device to configure it to use the fourth SCSI id? Remember, SCSI ids start with zero.
Answer: C
Correct answer: 011
SCSI IDs count from zero, so the fourth is ID 3, and 3 in three bits is 011. The two low jumpers are shorted and the high one left open.
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What does the term ‘plug and play’ mean?
Answer: C
Correct answer: A device is recognised and configured automatically when connected
Plug and play means the operating system detects a newly connected device, identifies it, and loads or obtains the appropriate driver automatically, without the user configuring anything. It is easy to underrate because it is now universal. Before it, adding a card meant setting jumpers or switches by hand to assign an interrupt request line, a DMA channel and an address range, and choosing values that clashed with an existing device produced failures that were exceedingly difficult to diagnose. It requires cooperation between the firmware, the operating system and the device itself, which must be able to report its identity. USB was designed around it and added hot swapping, so a device can be connected and removed while the machine runs. A driver is still needed, but the system now finds it - from its own store or over the internet - rather than requiring a disc.
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Which best describes a fragmented hard drive:
Answer: D
Correct answer: Files are not stored in consecutive clusters
Fragmentation is a matter of layout, not of damage: as files are created and deleted, a new file is written into whatever gaps exist, so its clusters end up scattered and the head must seek between them.
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Which of these connects a computer to a network?
Answer: A
Correct answer: Network interface card
A network interface card connects a computer to a network, either by Ethernet cable or wirelessly. It is now built into almost every motherboard rather than being a separate card, though the name persists. Every NIC carries a MAC address, a 48-bit identifier assigned at manufacture and written as six pairs of hexadecimal digits. It identifies the hardware itself and does not change when the machine moves to a different network - unlike an IP address, which is assigned by the network and does change. The two work at different layers: the MAC address delivers a frame within a local network, and the IP address routes a packet between networks. The other cards named are expansion cards serving different purposes: a sound card handles audio input and output, a graphics card renders the display, and a TV tuner receives broadcast signals. All plug into PCI Express slots on the motherboard.
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If a computer's BIOS allows it, you can boot from a CD-ROM.
Answer: A
Correct answer: True
The El Torito extension lets the BIOS read a bootable image from a CD, which is how operating systems came to be installed without floppies. The BIOS must support it and the CD must be earlier in the boot order.
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ISDN stands for:
Answer: B
Correct answer: integrated services digital network
ISDN carries voice and data over the same digital subscriber line, which is what integrated services means.
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