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What should you realize about the MMC/SD cards for m500/m505 devicesJun 01 '01 Write an essay on this topic.
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The Bottom Line The specifications of SD shows promise but there are no guarantees with this flash media type. MMC is too slow to access on a Palm and may frustrate users.
In just the past few months, Palm has released the m500 and m505 units which incorporated a few new features. One of the most notable is the new MultiMedia Card (MMC)/Secure Digital (SD) card slot on both of these units. Advertised by Palm as being... "The expansion card slot is a dual-purpose slot that can hold two types of cards: Secure Digital and MultiMediaCard. Both types of cards are small, inexpensive, and easy to plug in. Much like computer diskettes, they hold information for upload or download onto a handheld. With them, you can instantly add software programs, e-books, large databases, graphics, or even video files to your handheld without sacrificing memory space." Fine... that's what Palm says. The similarities between the MMC and SD card Basically, both are forms of flash memory that are non-volatile (no power needed to keep information stored) and are solid-state devices (no moving parts). Multiple manufacturer make and sell these cards. Prominent companies include SanDisk, Lexar, Viking, Simple Technology, and many more. Pricing for the various flash media can vary greatly with SD cards being the most expensive on a meg to dollar basis. The SD and MMC share a similar look although vary greatly on performance. They are about the size of a postage stamp (well a bit bigger and alot thicker than a postage stamp) and have for the most part the smallest form factor of the flash medias. Other flash media include CompactFlash and SmartMedia. CompactFlash has the largest form factor, but it contains the largest amount of memory and the best meg to buck ratio. Consider than 128MB of CompactFlash can be bought as low as $78... the buck-to-meg ratio is 61 cents per megabyte of storage. Also consider than CompactFlash goes upwards to 1 Gig of storage currently and you'll see why CompactFlash is such a widely supported standard as you can find in TRGPro handheld devices, Pocket PC devices, digital cameras, and even notebooks and desktop computers. SmartMedia is not nearly as widely accepted as CompactFlash but hundred... even thousands of devices support it. The media is larger in height and length over MMC and SD cards but the media is paper thin! Many MP3 players and digital cameras support this media. The maximum available storage for the card is 128MB although the more common cards come is 64MB sizes. 64MB costs as low as $44 (Yes, these prices exist on the web!). The buck-to-meg ratio is then 70 cents per MB. A little steeper but acceptable! MMC cards have been on the market for quite some time. They have not been as popular as CompactFlash or SmartMedia. Although the size of this media is extremely attractive. The pricing has not! A 32MB card costs as low as $55 at best. This is a buck-to-meg ratio of $1.70 a MB. Ouch. A 128MB card was in the $150 range. This is still in the $1.35 per MB range. SD is the newest kid on the block. The 16MB card costs as low as $40. This is a ratio of $2.50 a MB. That really sucks on your wallet! A 64MB card cost me $105. This was a ratio of $1.71 per MB. However, SD cards have some advantages over the MMC card and possibly the other Flash Media types. MultiMedia Card... The MMC Again, the MMC standard has been around for a couple of years. I became aware of the standard in 1999. The MMC format was codeveloped by SanDisk and Siemens Nov. 1997. The card is a little larger than a postage stamp with a seven pin serial interface. This interface would allow quick and easy device compatibility to a variety of devices without heavy hardware requirements supposedly. Regardless, the medium never got a strong foothold. The media got stuck at 64MB of storage although recently, 128MB of storage was slated to become available soon. Products such as the Compaq iPAQ MP3 player and the Nike PSA play series utilized MMC cards. Many older I-Jam MP3 players utilized them (this is how I got 2 16MB MMC cards for less than $40 with the MP3 player included!). The MMC are the cheaper storage choice between the MMC and SD cards. However, MMC access through the Palm m500 and m505 is rather slow. The Palm m500/m505 takes time to access the data on the MMC card which takes up to 2 minutes on my 16 MB MMC card. Photosuite takes up to 5 minutes to access information on the card. You get to use most of the MMC memory towards your storage needs. 0.7 MB is used by the Palm system for formatting. The Secure Digital card(SD), the improvements! These cards currently are available up to 64MB of storage although the road map for SD is very aggressive. Plans are to move up to 256 and 512 MB formats by the end of 2001 and 1 Gig in early 2003. The road map can be seen at: http://www.sdtrend.com/data/sdinfo/fast.html SD is capable of transferring data up to 2MB per sec per channel. Theoretically, 5MB/sec per channel is possible as well as 10MB/sec and 20MB/sec as total transfer speeds. There are 4 serial channels on a SD card that can be used in parallel. What this means is that you have a much faster and accessable flash media other than the MMC. The 16MB SD Expansion Card sold by Palm is notably faster than the MMC card. Most operations took less than 30 secs to search or execute. The big downside was that the formatting of the card only allowed 13.9 MB of the 16 MB available for your use. The 2.1 MB went into security measures!?!?! That is a lot of memory to sacrifice on a 16MB card. I am still awaiting my 64MB card to see how much is usable here. Good now I can have more memory on my Palm unit and blow everyone else out of the water! No... unfortunately, that's not how the MMC or SD cards work. The best way to describe how the MMC and SD cards work is by matching it to the flash memory modules of the Handspring. Most single file programs will run off the card (i.e. automatic transfer into current handheld memory then erase when finished using). Programs like ePocrates have multiple files. Only the executable file can be placed on the MMC or SD card but the databases and supporting files must be on the main 8MB of RAM on your Palm. That severely hampers the usefulness of the MMC and SD cards! Most programs currently do not support the use of the MMC/SD card, but many companies are upgrading their software. Handheldmed Reader program now supports the CF cards and MMC/SD cards in their ver 5.0 program. MGI Photosuite mobile also supports MMC/SD cards. Older programs do not support files and databases on the MMC/SD cards. Again, another limiting factor to the expansion card on the Palm m500/m505. Conclusions The SD slot is still an emerging medium but currently does not offer a great deal more than other Palm OS devices utilizing the Springboard modules or CompactFlash cards. Realize what you are currently getting into with SD/MMC expandibility on the m500 and m505. These cards are not a substitute for the actual RAM on the Palm unit... they supplement and support the 8MB on your Palm. On another note, this article is not meant to be the ultimate source of information on MMC and SD... just my current observations and experience with the media. I plan on updating this as new developments occur and as Palm OS programs are upgraded to work with MMC and SD. It is still early to tell where this media is heading... but there are some worries about the viability of if the Palm m500 is already being discounted to prices as low as $330 within 2 months of it's release. That's $70 off the retail price and I found that price at Best Buy this past weekend! I'm sure there are other members who are more knowledgable in SD and MMC out there. Comments and observations are definitely appreciated. Read my other Palm m500/m505 related reviews. Read my Palm m500 review here http://yusakugo.epinions.com/content_17605234308 Read my Palm m505 review here http://yusakugo.epinions.com/content_18495606404 Read my making Palm V/Vx accessories compatible with your m500/m505 unit here http://yusakugo.epinions.com/content_1585291396  |
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