From RB....
repost - Intel comments on flash memory management . . .
The Driving Need for Flash Software Management in Wireless
By Charles Brown, Intel Corp.
Cellular phones usage has dramatically changed. In the past, people relied on cell phones as a voice communication tool. Today, however, people depend on cell phone to be wireless information appliances that combine voice, paging, Internet, and e-mail services in a single, tiny handheld device.
The advantages of wireless information appliances are obvious: convenience, portability, and interoperability. With these devices you can process contact, scheduling, and task management information. You can access data from Internet sites while seated, walking, or driving. You can selectively synchronize and exchange data with notebook computers and other sources, such as wireless application protocol (WAP)-enabled Internet sites. These devices offer a raft of features, all delivering on the vision of true "anytime, anywhere" communication.
Flash memory provides an inexpensive and efficient way to store nonvolatile data and code. However, the distinct characteristics of randomly accessible flash memory require software management for it to function efficiently as a persistent data repository. The cost effectiveness of flash memory is achieved by organizing the memory in addressable ranges or blocks. The storage, access, and reclamation of data blocks in a real-time environment, such as a cellular phone, necessitates software intervention. In addition to basic data management, wireless Internet applications must address data throughput, common access formats, and security issues. These are just some of the memory subsystem challenges facing wireless designers.
Third-generation (3G) wireless handheld devices must allow users to gain access to new network capabilities and manage data records. The confined size, low cost, and restricted power of these 3G digital products place greater demands on the storage subsystem. In the past, designers used separate memory devices for storage of operational code and small, simple data structures such as contact lists. Now, size and cost stipulations dictate single-chip solutions for storage of both executable code and data. New wireless connectivity architectures, such as Bluetooth, link the handset to a vast reservoir of data storage capability on the notebook PC, satisfying the needs of the most demanding users.
Besides parameter storage, memory management software needs to perform a variety of tasks, such as invalid data management, power-loss recovery, and wear leveling. When a block of flash memory includes enough invalid data, valid information must be reclaimed by moving it to a new location in the flash component. Then the block can be erased. All of this takes place without affecting the applications that must continue to run.
Data Corruption Safeguards
Cellular/PCS phones must be safeguarded against data corruption. Complete power-loss recovery is essential to prevent this type of corruption. The idea is simple: don't invalidate the old occurrence of a parameter before assuring the new parameter has been safely written. However, the implementation is more complex and often overlooked.
A robust software media manager masks the physical attributes of the media from the application and network control code managing the appliance function. A common programming interface to the media manager provides easy access to data by applications. Thus, the flash media manager needs to be part of the baseware functions with a basic programming interface (See Figure).
Flash software management programming model
The storage functions for next-generation handsets must accommodate a variety of data structures; variable-size parameters to hold a single-byte device setting such as volume level up to hundreds of bytes for short message services and e-mails. For example, digital audio recording mandates the storage of data streams of unknown length and a means of quickly searching these structures to aid in voice recognition.
New communication specifications, such as Bluetooth, enable seamless, high-speed transfer of data packets between the notebook PC and digital phone. The handset flash memory manager must have knowledge of the size and rate of data transmission to avoid overflowing the memory. This is an issue regardless of the background program and erase capability of the silicon. Poor media management could result in slow, inefficient storage or interrupted transmission.
Whether the configuration of the flash memory is standard, read-while-write, or multiple chips packaged in a single module, software is always required to efficiently manage code and data and to provide a common storage interface to the application. As flash memory management techniques advance, the designer must reconcile the trend toward enriched data management while also balancing cost and hardware capability.
As cell phones become more sophisticated, the technical challenges to wireless designers increase accordingly. The approach to flash memory management must grow with the sophistication of the appliance. The management software should provide a small memory footprint and support a wide range of data structures. This allows the software to serve equipment from digital phones up to handheld multimedia platforms.
The primary reason you want to own a data-rich phone is to carry, and access quickly, information you might otherwise store only on your PC system. For this model to remain effective, you must keep the two sets of data consistent. Consequently, simple synchronization is a key ingredient in the recipe for handheld wireless appliances. Designers must now turn to a comprehensive software manager to balance handset cost with the data storage needs of feature-rich wireless appliances.
repost - Inel comments on flash memory management . . .
The Driving Need for Flash Software Management in Wireless
By Charles Brown, Intel Corp.
Cellular phones usage has dramatically changed. In the past, people relied on cell phones as a voice communication tool. Today, however, people depend on cell phone to be wireless information appliances that combine voice, paging, Internet, and e-mail services in a single, tiny handheld device.
The advantages of wireless information appliances are obvious: convenience, portability, and interoperability. With these devices you can process contact, scheduling, and task management information. You can access data from Internet sites while seated, walking, or driving. You can selectively synchronize and exchange data with notebook computers and other sources, such as wireless application protocol (WAP)-enabled Internet sites. These devices offer a raft of features, all delivering on the vision of true "anytime, anywhere" communication.
Flash memory provides an inexpensive and efficient way to store nonvolatile data and code. However, the distinct characteristics of randomly accessible flash memory require software management for it to function efficiently as a persistent data repository. The cost effectiveness of flash memory is achieved by organizing the memory in addressable ranges or blocks. The storage, access, and reclamation of data blocks in a real-time environment, such as a cellular phone, necessitates software intervention. In addition to basic data management, wireless Internet applications must address data throughput, common access formats, and security issues. These are just some of the memory subsystem challenges facing wireless designers.
Third-generation (3G) wireless handheld devices must allow users to gain access to new network capabilities and manage data records. The confined size, low cost, and restricted power of these 3G digital products place greater demands on the storage subsystem. In the past, designers used separate memory devices for storage of operational code and small, simple data structures such as contact lists. Now, size and cost stipulations dictate single-chip solutions for storage of both executable code and data. New wireless connectivity architectures, such as Bluetooth, link the handset to a vast reservoir of data storage capability on the notebook PC, satisfying the needs of the most demanding users.
Besides parameter storage, memory management software needs to perform a variety of tasks, such as invalid data management, power-loss recovery, and wear leveling. When a block of flash memory includes enough invalid data, valid information must be reclaimed by moving it to a new location in the flash component. Then the block can be erased. All of this takes place without affecting the applications that must continue to run.
Data Corruption Safeguards
Cellular/PCS phones must be safeguarded against data corruption. Complete power-loss recovery is essential to prevent this type of corruption. The idea is simple: don't invalidate the old occurrence of a parameter before assuring the new parameter has been safely written. However, the implementation is more complex and often overlooked.
A robust software media manager masks the physical attributes of the media from the application and network control code managing the appliance function. A common programming interface to the media manager provides easy access to data by applications. Thus, the flash media manager needs to be part of the baseware functions with a basic programming interface (See Figure).
Flash software management programming model
The storage functions for next-generation handsets must accommodate a variety of data structures; variable-size parameters to hold a single-byte device setting such as volume level up to hundreds of bytes for short message services and e-mails. For example, digital audio recording mandates the storage of data streams of unknown length and a means of quickly searching these structures to aid in voice recognition.
New communication specifications, such as Bluetooth, enable seamless, high-speed transfer of data packets between the notebook PC and digital phone. The handset flash memory manager must have knowledge of the size and rate of data transmission to avoid overflowing the memory. This is an issue regardless of the background program and erase capability of the silicon. Poor media management could result in slow, inefficient storage or interrupted transmission.
Whether the configuration of the flash memory is standard, read-while-write, or multiple chips packaged in a single module, software is always required to efficiently manage code and data and to provide a common storage interface to the application. As flash memory management techniques advance, the designer must reconcile the trend toward enriched data management while also balancing cost and hardware capability.
As cell phones become more sophisticated, the technical challenges to wireless designers increase accordingly. The approach to flash memory management must grow with the sophistication of the appliance. The management software should provide a small memory footprint and support a wide range of data structures. This allows the software to serve equipment from digital phones up to handheld multimedia platforms.
The primary reason you want to own a data-rich phone is to carry, and access quickly, information you might otherwise store only on your PC system. For this model to remain effective, you must keep the two sets of data consistent. Consequently, simple synchronization is a key ingredient in the recipe for handheld wireless appliances. Designers must now turn to a comprehensive software manager to balance handset cost with the data storage needs of feature-rich wireless appliances.
v |
