Actually, there's no such thing as dual-channel DDR memory. There are, however, dual-channel platforms. If you have a dual-channel platform, simply purchase your DDR memory in pairs. However, be very careful to order two modules with the exact same specifications; the modules must be identical to each other to perform correctly.

Ans: To answer this question you really have to break down how it is that companies "certify" or "match" Dual Channel memory modules. What is Matched or Certified Dual Channel Memory? Companies like Corsair, OCZ, and Mushkin produce what they call "dual channel" memory, or Dual Channel Kits. These are sold in pairs, so for instance you might buy a 512MB or 2x256MB Dual Channel Kit, which consists of 2 sticks 256MB DDR memory paired together by the manufacturer.

SDRAM (single dynamic randomn access memory) is the older style of memory with 2 notches on the stick. The speed of SDRAM is either 100 or 133 MHz (older SDRAM was 66 MHZ - do not mix with pc133 memory !) DDR (double dynamic rate) memory has only 1 notch. The DDR memory will read twice (double) as much information as the SDRAM - the speed of DDR is from 266 to 400 MHz

Your system board will support this new memory if you have the PE desktop model. Please check the parts list to verify which memory speed your system is equipped with. If you have 266MHz memory and wish to upgrade, please ask your store technician to help you upgrade to 333MHz.

Joint-Stereo - This method of encoding combines duplicate (or "perceptually similar") information from the Right and Left channels in an effort to most efficiently compress the file. This way the duplicate information is only encoded *once* instead of twice (one time for each channel) and allows for more bits to be allocated to the other non-duplicate information.

Normal ISDN service is BRI or 2B+D, and gives you two 64 kBPS channels that can be used for voice or data. An ISDN modem can use both channels at the same time, giving you a 128 kBPS Internet connection.

There is no such thing. Dual Channel is a feature of the chipset, so there is no requirement to spend more money on a "Dual Channel Kit".

Day Delegate Rate. This is the cost per person in hiring the conference room. Day Delegate Rates normally come as a package typically including room hire, teas/coffees and lunch. DDR packages will vary from operator to operator and package to package.

No, you can't. DDR memory is not backwards compatible. And you most likely can't use EDO. The bx chipset indeed has support for EDO memory, but most boards don't (an exception to that are the bx based boards from supermicro). If you really happen to have a board which has support for EDO modules (check your manual) you can't mix EDO rams with PC66/100/133 sdrams, and you can only run at 66mhz FSB (that is, you'd have to use a P2 up to 333mhz or a Celeron up to 766mhz).

No, DDR2 DIMM memory modules are not backwards compatible with DDR DIMM, due to incompatible pin configurations, core voltage, and memory chip technology. DDR2 modules are designed with a different "key" in the edge connector to prevent insertion into incompatible memory sockets such as DDR motherboard. A DDR2 SDRAM DIMM will not fit into a standard SDRAM DIMM socket or a DDR DIMM socket. DDR2 modules use a 1.8V power supply, providing a big power saving over the 2.5V DDR modules.

A full detail explanation and product guidelines for memory modules and DDR applications can be found in our Applications section under Memory Modules.

Absolutely not. You can use DIMMs from different manufacturers, with different sizes and different timings. You will get the lowest common denominator though, which means that timings will be as for the slowest DIMM in there. The first channel is the two slots nearest the CPU, the second channel is the slot furthest from the CPU. You may put 1 or 2 DIMMs in the first channel and as long as there is a DIMM in the second channel, you'll have Dual Channel.

Dual Ported Memory can be accessed in one of two ways. Using the POSIX compliant shared memory routines, the memory object "Physical" can be opened with shm_open(). A particular offset into memory is then mapped in with mmap(). The flags parameter must use MAP_SHARED, and protections should include PROT_NOCACHE. The second method to accessing dual ported memory is to use the qnx_segment_overlay() routine to create a segment that points to the memory.

There are two main differences between a signal channel Q406 and a dual channel Q406. First, only the single channel modules have a reverse / direct switch. The reverse mode allows the Q406 to have an increasing output with a decreasing input. Second, only the single channel module has a 0-20 mA output range. Both single and dual channel units have the 0-1 mA, 4-20 mA, 0-5 V and 0-10 V output ranges. The best product to use is the Q406 for AC powered modules or a Q408 for DC powered modules.

Important Note: Your humble authors got tired of writing dry formal technical prose in the rest of this document, and succumbed to the temptation to try to be funny in parts of this appendix. Sarcasm abounds here. Please do not take any of this personally! The humor-impaired should interpret my comments not as attacks on them, but as an attempt to make fun of myself for being impatient with you, my devoted and valued, if sometimes demanding, users.

Consult your user/owner's manual for details about the original memory configuration and capacity. If you've misplaced the manual, you may be able to contact the retailer where you bought the PC from. If you have a hand-me-down PC or inherited a pre-owned PC, you probably may not have the user manual or know any detail of the original memory configuration or the memory configuration may have been changed.

Before purchasing, note whether your system takes 16 bit or 32 bit RIMM modules. Please check with your motherboard vendor for detailed information. In most case you must upgrade each channel equally. 32bit RIMM modules, such as RIMM 4200, 4800, 6400 modules can be upgraded singly on dual channel systems.

A 168 Pin Dimm is approximately 5 ¼ inches in length and 1 inch in height and contains 84 Pins on either side. It is referred to as a 168 Pin Dimm because it reads both sides of the Dimm simultaneously. The Dimm is different from the Simm in that it has two notches on the contact edge and inserts into the socket straight down, without the need for tilting. Dimm sockets also have release tabs at each end which acts as a lever to push the module up out of the socket during removal.