RAM chips

In a similar fashion, computer memory and data transfer rates have also increased since 1993. Intel introduced the first ever RAM chip in 1970 with 1024 bits of storage space and a transfer rate of 500 Hz. In 1994, a typical PC had 16 MB of RAM with a transfer rate of 66 MHz. And in 2010, typical PC memory can be up to 64 GB in 8 GB modules with 1033 MHz transfer rate. It is the access to this level of technology today that enables spectral simulation calculations to take place on a single user workstation that would previously have required mainframe or even super-computer performance. 

The major class of digital ICs is the CMOS. The most familiar CMOS applications include microprocessor and RAM chips. As its name implies, CMOS technology involves the complimentary operation of interconnected nMOSFET and pMOSFET pairs (Figure4.22). Relative to NMOS or PMOS integrated circuitry, CMOS is the... 

DRAM DRAM is dynamic random access memory. This is actually the RAM that most people are talking about when they mention RAM. When you expand the memory in a computer, you are adding DRAM chips. The reason you use DRAM to expand the memory in the computer is because it s cheaper than any other type of memory. Dynamic RAM chips are cheaper to manufacture than other types because they are less complex. Dynamic refers to the chips need for a constant update signal (also called a refresh signal) in order to keep the information that is written there. 

Memory test failed. One or more portions of RAM were found to be bad. Any numbers following this error code may indicate which RAM chip is bad. See the computer s documentation for information on interpreting those codes. 

Chip creep can affect any socketed device, including ICs, RAM chips, and expansion cards. The solution to chip creep is simple. Open the case and reseat the devices. It s surprising how often this is the solution to phantom problems of all sorts. 

Computers are like human beings. They have similar tolerances to heat and cold (although computers like the cold better than we do). In general, anything comfortable to us is comfortable to a computer. They need lots of clean, moving air to keep them functioning. They don t, however, require food or drink (except maybe a few RAM chips now and again ). Keep food and drink away from the computer. 

Single Inline Memory Module (SIMM) Individual RAM chips are soldered or surface mounted onto small narrow circuit boards called carrier modules, which can be plugged into sockets on the motherboard. These carrier modules are simple to install and occupy less space than conventional memory modules. 

RAM memory can be written to the computer system, the interference signal against the lower RAM data can be tampered with, procedures and forms may remain in the program memory EPROM avoid this data is subject to interference and sabotage in the SCM system, But for the on-chip RAM, chip, plug-in RAM data are likely to be interfered change. 

The same coating is also used to protect static RAM chips from alpha particle radiation, which can cause soft errors, and it reduces the probable failure rate by at least one order of magnitude. Calculations indicated that a 0-5 mm layer would stop 8 MeV alpha particles, and that the coating was fully compatible in all respects. The authors reported that the resultant soft error rate of 0-1% per 1000 h established in service was the lowest level of activity observed for any packaging material presently in use. 

The PCBA (Printed Circuit Board Assembly) Operations Division of MSM in Singapore deals with the assembly of RAM chips using TSOP (Thin Small Outline Package), DRAMs, PCBs (Printed Circuit Board) and other discrete components. A typical module consists of a number of memory components that are attached to a printed circuit board. The gold or tin pins on e bottom of the module provide a connection between the module and a socket on another larger PCB. There are also some eapaeitors and resistors soldered onto the PCB. 

RAM consists of four static RAM chips, 8k x 8-bit each. Because of the low power consumption, memory chips can be powered from the built-in rechargeable battery for up to 30 days. 

Addressing is achieved through 14 address lines. Lines AO to A9 are directly connected to RAM chips. They come from latches 8282, sheet 4. Signals PO, PI, P2 and P3 indirectly involved in the addressing are generated by the programmable chip A26, sheet 5. It accepts the address lines from AlO to A15 from circuit A47 and provides outputs with respect to the memory organization. 

Pi line together with the latched applied to A62, 3 to 8 lines decoder, of A62 are used to enable RAM chips. 

Because the transputer has a 32-bit processor and fast access to considerable quantities of on-chip RAM, it has been called a computer on a chip. Transputers are inherently faster than microprocessors, which have to refer to RAM outside the chip on which they reside. Thus the 100-nsec cycle time used in the above illustration may be only 50 nsec when carried out on the transputer chip. 

SCREEN will run on an IBM-PC compatible personal computer with at least 2S6K of RAM. The program will run with or without a math coprocessor chip. Execution time will be greatly enhanced with a math coprocessor chip present (about a factor of S in computer time) and will also benefit from the use of a hard disk drive. 

Sponsor/Developing Organization LLNL. Developer. Steven G. Homann, LLNL L 380, P.O, Box 808, Livermore, CA 94551 Phone (501) 423-4962, Fax (501) 423-3090, E-mail shomann llnl.gov. Custodian Same. Hardware IBM PC compatible with a 80286 processor or greater, 512 kB of RAM, Microsoft DOS version 3.0 or later. Math coprocessor chip is desirable optional, hut highly recommended, 0.5 MB hard disk space. Software Pascal, tyjjical mn time several seconds. Cost No charge from LLNL. 

Benchmarq Microelectronics, Inc., designed a special (more expensive) charging chip for RAM cells, connected in series [40]. The advantage is a complete disconnection of the load when the first cell reaches the predetermined cut-off voltage. Cell reversal is thereby eliminated. 

There are two types of memory used in computers. The main memory is based on integrated circuit chips and all parts can be accessed with great rapidity and with equal ease. In mainframe computers this is known as the main store whilst in smaller computers, including microcomputers, it is called the random access memory (RAM). Some parts of RAM may be reserved for the storage of programs or data which are to be protected from change or accidental erasure. Such a reserved area of memory is called read only memory (ROM). ROM chips, sometimes called firmware, are often used in integrators and microcomputers dedicated to particular tasks. The... 

Storage requirements This is the main cost factor for implementations on dedicated silicon (single chip encoders/decoders). RAM costs are much higher than ROM cost, so RAM requirements are most important. 

The memory organization of DSPs are also different from ordinary processors because (1) Memory is typical static RAM and virtual memory support is totally absent (2) Several machines separate data and instruction streams (Harvard Architecture) (at the cost of extra pins). Additionally, modular arithmetic address modes have been added to most processors. This mode finds particular utility in filter coefficient pointers, ring buffer pointers and, with bit reversed addressing, FFTs. One further difference is the use of loop buffers for filtering. Although often called instruction caches by the chip manufacturers, they are typically very small (for example, the AT T DSP-16 has 16 instructions) and furthermore, the buffer is not directly interposed between memory and the processor. 

For non-volatile random access memories (NV-RAMs in which the stored information is retained even if power to the chip is interrupted), ferroelectrics serve not just as capacitors (as in the case of the DRAM, described below), but as the memory element itself. Their principal advantages in this application are low-voltage (1.0 V) operation, small size (about 20% of a conventional EEPROM cell - and cost is proportional to size once high-yield production is achieved), radiation hardness (not just for military applications but also for satellite communications systems) and very high speed (60 ns access time in commercial devices, sub-nanosecond in laboratory tests on single cells). 

The MMU controls whether the VIC chip or 80-column chip controls screen display, and even senses the position of the 40/80 DISPLAY switch (though the software must interpret this switch). The MMU controls access to RAM or ROM, allowing either to be visible in the memory map. A programmer can set up a series of preset memory configurations and quickly select them by writing to the MMU. The address of the VIC chip can be relocated an5rwhere within the virtual 256K memory space. 

I he spine of the computer is the system board, otherwise known as the motherboard (and less commonly referred to as the planar board). This is the olive green or brown fiberglass sheet that lines the bottom of the computer. It is the most important component in the computer because it is the component that connects all the other components of a PC together. Figure 2.2 shows a typical PC system board, as seen from above. It is on this sheet that all other components are attached. On the system board you will find the CPU, underlying circuitry, expansion slots, video components, RAM slots, and a variety of other chips. 

Memory or random access memory (RAM) slots are the next most prolific slots on a motherboard, and they contain the actual memory chips. There are many and varied types of memory for PCs today. In this chapter, you will learn the appearance of the slots on the motherboard, so you can identify them. You will learn more about the details of the different types of PC memory in Chapter 3, PC Memory Architecture. ... 

---