PC RAM Manufacturing in Action

On the software development front it is well known that India does has a strong position, but when it comes to manufacturing of critical IT hardware components like processors or memory modules, very few manufacturers are there. Om Nanotech is one of those few Indian manufacturers who manufacture DRAM memory modules. Still, the main silicon chips are not manufactured but sourced from manufacturers like Micron, Samsung etc. They manufacture the DRAM and Flash memory modules under brand name ZipMem. PCQuest had the opportunity to visit their manufacturing facility in NOIDA to see the manufacturing process and to talk to Atul Khosla, Director, Om Nanotech, who talked about the technologies of DRAM, Flash and SSDs.

Q> Please demystify DRAM and Flash memory and tell us where each is used?

DRAM and Flash are sometimes confused to be similar but there are many noticeable differences. DRAM is a Dynamic random access device and hence, is extremely fast for read-write operations. On the other hand NAND Flash takes relatively long times (latency) before giving a burst of data. To put things in right perspective, on an average NAND has a 25 micro second latency. However, it is around thousand times slower than the 20-25 nanoseconds access time for DRAM.

While the above statistics might show NAND in poor light, however, it may be noted that NAND is still hundred times faster than the average latency time for a hard disk. DRAM also has faster write speed than those of NAND. The con with DRAM is that it consumes much more power to retain data and so it must be continuously refreshed whereas NAND can store data without the need of electrical backup. DRAM is packed in higher density and hence, for the same amount of storage requires less physical space. Last but not the least, Flash is cheaper as compared to DRAM. Therefore, DRAM will continue to have its relevance where faster access of data is required like in case of memory for servers, desktops, notebooks and other memory cache devices. On the other hand Flash shall be preferred medium for off-line storage and even extended memory, for instance Windows 7 can use a pen drive as an extension of onboard RAM, or used as internal memory in tablets and smartphones.

Q> How are these two technologies being used in SSDs? Would SSDs be able to replace conventional HDDs?

Yes, in coming times we'll see more & more HDDs being replaced by SSDs. The reason for that is simple, SSDs do not have any moving parts and as such do not deteriorate as HDDs. As evident from above, the two technologies will continue to co-exist due to their relevance for specific applications. However, in recent times there have been trends to merge the two like in case of some SSDs, a DRAM buffer is provided to provide faster access to data. The data to be written on the Flash in SSD is held in a DRAM buffer and transferred to Flash as and when possible by the onboard controller in the SSD. On the other hand SSDs are reliable, they come in the same form factor as an HDD, consume lesser power, are more rugged, can absorb shocks even when in use, work at higher temperatures, which is critical especially in defense and industrial applications. Due to its lower power consumption, SSD generates lesser heat as compared to an HDD. The negative factor for SSD used to be the higher price and also to some extent the limited no. of read and write cycles. However, with DRAM cache and intelligent controllers this limitation has been practically removed.