The Differences Between Similar Technologies, Part 2

A few weeks ago in part 1 we examined five often misused or misunderstood terms in the computing world. Today we’re going to take a look at five more industry terms that many people are confused about or use interchangeably in the wrong context.

1. BIOS and CMOS. BIOS stands for Basic Input/Output System, and CMOS stands for Complimentary Metal-Oxide Semiconductor. The BIOS refers to the chip on your motherboard that contains software which regulates and assigns system resources based on your hardware configuration. It keeps track of your disk drives, onboard peripherals, power-saving functions, and boot options. Unfortunately the BIOS does not have a way to save this information within the BIOS chip itself. Therefore it must rely on the CMOS to hold these important settings. CMOS can refer to any number of semiconductor transistors, but in this case we’re talking about a type of memory for holding BIOS information. The CMOS chip on a computer’s motherboard is basically a low-power memory chip which can be reset by cutting the power source. CMOS uses a battery on the motherboard to retain its settings when the power is not on; to reset the CMOS settings (which sometimes must be done when changing a CPU) you can either remove that battery or use the CMOS Clear jumper to cut the power to the chip, thereby erasing it and forcing the BIOS to use factory default settings.

2. Dual-Channel DDR. DDR stands for Double Data Rate, and it is a type of SDRAM (Synchronous Dynamic Random Access Memory). DDR means that data can be transferred on both the rising and falling edges of a clock cycle, which is twice as much data per cycle than standard SDRAM. The clock speed of DDR memory is therefore interpreted as double its actual number; DDR400 runs at an actual speed of 200mhz, for instance. Dual-Channel DDR does not exist — there is no such thing as Dual-Channel DDR memory. When we say Dual-Channel in regards to memory, we’re referring to the memory controller (northbridge) of the motherboard. The Intel 850E, Intel E7205, SiS 655, Intel 865, and Intel 875 chipsets all use Dual-Channel memory controllers. So what does Dual-Channel mean? A channel is a physical pathway for data to travel. Dual-Channel memory controllers have two separate channels for data, thereby doubling the potential theoretical memory bandwidth. The nForce2 chipset uses two separate memory controllers, so it is not quite the same thing although Nvidia calls it DualDDR and it does increase the theoretical memory bandwidth far beyond the actual limitations of current and future AMD CPUs.

3. Hyper-Threading, HyperTransport and Multithreading. Hyper Transport is a technology (developed in part by AMD) that increases bandwidth and data throughput in integrated circuits (a CPU is an example of an integrated circuit) by reducing latency (the time it takes for a data request to be fulfilled). It can be used in nearly any electronic device that uses ICs, but currently it is most commonly found in AMD CPUs and the motherboards that use them. Hyper-Threading Technology was developed by Intel and it is a modification to their Pentium4 CPU design, allowing two threads (program instructions) to share the same data pathway. That means that the CPU can literally do two things at once — true multitasking. HT Technology is integrated into the 3.06ghz Pentium4 CPU, all 533FSB Xeon CPUs, and all 800FSB Pentium4 CPUs. Multithreading is the process that multiple-CPU systems use to handle program instructions. It is more efficient than Hyper-Threading because there is more processing power available for separate threads. Multithreading is only useful when multitasking or when using a program that heavily stresses the CPUs and is designed for a multi-CPU architecture.

4. Free Software and Freeware. The Free Software Foundation defines Free Software in terms of rights, not price. So Free Software is more akin to “free speech” than it is to “free beer.” What it means is that the user is free to use, distribute, study, modify and adapt the software. Free Software is not always free in terms of price, nor does it have to be. Indeed you should pay for or make a donation to the company or organization who spent time and money making the software that you use, but you are not required to do this. Freeware does not have a specific agreed-upon definition, but the term was coined in the late 80s when executable programs were distributed for free, often with limitations or shortcomings that could only be solved by purchasing the commercial version of the program. Freeware is proprietary, copyrighted software, and Free Software is both open-source (the source code is freely available) and owned by the Free Software community — not held by one specific individual or corporation. Free Software is a social movement that views proprietary software as unethical because it restricts our rights and infringes upon our freedoms. For more information on the Free Software movement, click here.

5. PCMCIA, PC Card, PCI Card and Smart Card. PCMCIA is the name of a standards organization (Personal Computer Memory Card International Association), which published the currently-used standard for PC Cards. PC Cards are credit-card-sized devices that interface with a computer (generally a laptop/notebook computer, although some PDAs and printers now have them and you can get PC Card readers for desktop computers as well). There are three types of PC Cards, and they are categorized according to size: type I is for memory cards and it is 3.3mm thick; type II is primarily for I/O devices like modems, soundcards, and network cards, and it is 5mm thick; type III is generally for PC Card hard drives and it is 10.5mm thick. The smaller cards will work in the larger slots, so the type I will fit in type II and III slots. All PC Cards connect with a 68-pin array, which transfers both the data and the power to the device. CardBus is a type of PCMCIA card that can use Direct Memory Access, has a 32-bit data path, and uses less power but otherwise is the same as any other PC Card. Another type of PCMCIA card is the ZV port card, which adds full-screen motion video functionality to a computer. PCI stands for Peripheral Component Interconnect and it refers to the infrastructure that connects devices to the CPU. PCI operates at a frequency of 33 or 66mhz and it uses a 32-bit data pathway. All PCI cards have 124 pins and are powered through the PCI slot on the motherboard. The PCI bus connects everything in the computer with the CPU and acts as the primary data pathway in the system. Most of the time when we refer to PCI it’s in regards to a PCI peripheral card like a modem or SCSI card. Smart Cards do not interface directly with computers; they are basically credit cards with integrated circuitry to help prevent theft and fraud.

Remember: never be afraid to ask if you don’t know.

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Copyright 2003 Jem Matzan. Verbatim copying and redistribution of this entire article are permitted without royalty in any medium provided this notice is preserved.

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