Hard Drives
Laptop computers use a smaller form factor of hard drive than their desktop counterparts. Mobile hard drives are typically 2.5” in size, versus a 3.5” in size for desktop computers. Because of their smaller physical size, laptop hard drives trail desktop hard drives in the amount of storage they can contain. Whereas in early 2008 desktop hard drives have reached 1 terabyte in size, laptop hard drives are maxed out at 250GB. Most manufacturers put 500-750GB hard drives in desktops while most laptop manufacturers build notebooks with 80-120GB drives.
Laptop Hard Drive
Desktop Hard Drive
Expansion
Expansion of a laptop usually takes one of two connections: PCMCIA or USB.
A PCMCIA slot is an expansion slot accepting standard cards about the size of 20 business cards stacked. As a computing standard, PCMCIA cards come in a wide variety of purposes including TV tuners, network adapters, cellular cards, or sound cards.
Almost all notebook computers (less some ultra-lightweight computers) support PCMCIA expansion cards. The PCMCIA association has since renamed the card as a “PC Card” but the exam should call it a PCMCIA card.
There are several types of PCMCIA cards, described below from Wikipedia’s PCMCIA description (http://en.wikipedia.org/wiki/PC_card):
All PC Card devices use an identical 68 pin dual row connecting interface. All are 85.6 mm long and 54.0 mm wide. This is the same size as a credit card. The form factor is also used by the Common Interface form of Conditional Access Modules for DVB broadcasts.
The original standard was defined for both 5 volt and 3.3 volt cards. The 3.3 V cards have a key on the side to protect them from being damaged by being put into a 5 V-only slot. Some cards and some slots operate at both voltages as needed. The original standard was built around an 'enhanced' 16-bit ISA bus platform.
Type I
Cards designed to the original specification (version 1.x) are type I and feature a 16-bit interface. They are 3.3 mm thick. Type-I PC Card devices are typically used for memory devices such as RAM, flash memory, OTP, and SRAM cards.
Type II
Type-II PC Card devices feature a 16- or 32-bit interface. They are 5.4 mm thick. Type-II cards introduced I/O support, allowing devices to attach an array of peripherals or to provide connectors/slots to interfaces for which the host computer had no built-in support. For example, many modem, network and TV cards use this form factor. Due to their thinness, most Type II interface cards feature miniature interface connectors on the card which are used together with a dongle; a short cable that adapts from the card's miniature connector to an external full-size connector.
Type III
Type-III PC Card devices are 16-bit or 32-bit. These cards are 10.5 mm thick, allowing them to accommodate devices with components that would not fit type I or type II height. Examples are hard disk drive cards, and interface cards with full-size connectors that do not require dongles (as is commonly required with type II interface cards).
Type IV
Type-IV cards, introduced by Toshiba, have not been officially standardized or sanctioned by the PCMCIA. These cards are 16 mm thick.
CardBus
CardBus are PCMCIA 5.0 or later (JEIDA 4.2 or later) 32-bit PCMCIA devices, introduced in 1995 and present in laptops from late 1997 onward. CardBus is effectively a 32-bit, 33 MHz PCI bus in the PC Card form factor. CardBus includes bus mastering, which allows a controller on the bus to talk to other devices or memory without going through the CPU. Many chipsets are available for both PCI and CardBus, such as those that support Wi-Fi.
The notch on the left hand front of the device is slightly shallower on a CardBus device, so a 32-bit device cannot be plugged into a slot that can only accept 16-bit devices. Most new slots are compatible with both CardBus and the original 16-bit PC Card devices.
The speed of CardBus interfaces in 32 bit burst mode depends on the transfer type; in byte mode it is 33 MB/s, in Word mode it is 66 MB/s, and in DWord mode it is 132 MB/s.
User Input Devices
There are several types of user input devices available on laptop computers: keyboard, trackpad, eraser-head style pointer, trackball.
The user input devices are slightly different on mobile devices than their desktop counterparts. Typical laptops have a “full size” keyboard with no numeric keypad. Smaller, lightweight notebooks have smaller, condensed keyboards.
With a built in trackpad, eraser head style pointer, or trackball, controlling the mouse is slightly different on a laptop. Most laptops have a USB port or Bluetooth to use an external mouse if the user desires.
Difference Between Desktop and Mobile Technologies
There are many differences between desktop computers and mobile computers, as illustrated in the discussion of different parts of notebook computers above.
The primary technology differences between a laptop and desktop come from the requirement for low power consumption and small form factor for laptop computers. This requires processors which use less money, circuit boards which take up less space, and an overall design which can fit into a unit no bigger than three inches high while closed.
Notebook computers use power management to control the amount of power it uses to increase battery life time. Power management does a combination of things, including slowing down the hard drive, dimming the monitor, and throttling down the processor to reduce power usage.
Mobile computers are also more likely to use wifi than desktop computers. Since the computer is more mobile, it is likely to have wireless networking built-in to take advantage of wireless hotspots and corporate wireless implementations.
Comments