Total Recall is a Psion Teklogix utility developed to maintain the persistence of installed applications and setting over cold boots and is based on a backup and restore concept, extended to incorporate powerful advanced features.
According to Psion Teklogix Country Manager, Raymond Hoy, Total Recall is available with all newly releases CE.NET Psion Teklogix hand held terminals.
This software package is a Control Panel applet with a wizard driven interface. Four options are available: Creating a backup profile, restoring a profile, viewing the contents of a profile, and deleting a profile.
A profile is a single, compressed file containing all of the files/databases/registry data that the user has chosen to backup. If the user has selected 8 MB of files/databases/ registry, the profile can be expected to be around 4 MB in size. The profile is composed of two basic elements: * Archive header: Describes a single compressed data section. It describes its compressed length, its uncompressed length, and information such as what the data represents (a file, part of a file, a database mount, or a registry file). * Compressed Data: The data may represent a file (or part of a file), mounted database volume or a file that represents the registry.
Each profile consists of many of these archive pairs which are grouped linearly by the type of data they represent: First, the array of archive header/compressed data that represents the compressed files, second the database archive pair and last, the registry archive pair.
Below are more detailed descriptions of the process for each type:
Files:
After a user has made file selections, Total Recall starts the process of finding each selected file (or if all are selected, it traverses the root directory). Files possessing the following file attributes are not included in the backup profile, as they are already in the default image:
* FILE_ATTRIBUTE_ROMMODULE
* FILE_ATTRIBUTE_INROM
Files without the above restrictions are deemed `backup candidates` and are put into a list. At profile creation, files are chosen first for backup. Each file is first checked to make certain it exists (the user may have removed the storage media). Next, Total Recall determines if the file needs to be split into smaller pieces (chunks) because of the large amount of overhead memory needed to compress the data (some units lack the memory necessary to achieve compression buffers for files that are several MB in size). The chunks are compressed and an archive header appended to each one to identifies it with a particular file, and is immediately written to disk (this helps keep memory usage to a minimum). This process is repeated for each file.
When Databases for backup is selected, the user accesses all with two exceptions: DB_notify_queue and DB_notify_events which are NOT included as they are in use by the system). A database is mounted on the storage device targeted for the backup profile, and the contents of the current database are copied to that external database. When a database is mounted to an external storage device, it creates a volume file with all of the information about the database and this file is acquired, compressed, and added to the profile.
Registry:
Using WinCE APIs, Total Recall creates a single file that contains the entire contents of the WinCE registry. This file is then compressed and written to the storage device.
Profile Settings:
The AutoRestore Profile setting will allow the user to create three different types of profiles: "Not an AutoRestore Profile", "AutoRestore Profile for this device only" and "Clone Profile for other devices" option.
The Profile Location section will allow the user to specify where the profile is to be saved. The location for the profile will typically be Flash or a Storage card.
Adding Files:
By default the `all files` option is selected which will save all installed or copied files, database entries, as well as the Registry. The user can however specifically backup the database, and or registry only.
The backup Individual file option gives the user the ability to explicitly select the exact file or files they would like to backup. With the by File Type option the user can select by predefined file types. The predefined types are *.lnk, *.dat, *.dll, *.lib, *.exe.
View Selections:
Depending on what has been selected to include in the profile, users will be able to view a listing of the selected files, databases, and or registry. The listing will not be editable.
Restoring a Selected Profile:
This option will allow the user to manually restore either one of the three types of profiles that they have created. Once a profile has been restored the unit will be reset in order for all changes to be applied.
Deleting Profiles:
The Delete Selected Profile option will delete any of the three types of profiles created. The profile may exist in Flash or on a storage card. Once select the user will be prompted to confirm their decision and the profile will be permanently deleted.
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