USB DEVICE SUPPORT in .NET

Printer QR Code in .NET USB DEVICE SUPPORT
USB DEVICE SUPPORT
QR Decoder In .NET Framework
Using Barcode Control SDK for .NET Control to generate, create, read, scan barcode image in Visual Studio .NET applications.
13.6.4 The mass storage le system
QR Code ISO/IEC18004 Printer In .NET
Using Barcode drawer for Visual Studio .NET Control to generate, create QR Code ISO/IEC18004 image in .NET framework applications.
This is quite different from any other le system. It contains null implementations of the le system API described in Section 9.4.1, and, when it is mounted on a drive, that drive is inaccessible from the Symbian OS device. Instead, the desktop host computer is allowed exclusive block level access to the drive. The mass storage le system implements the mass storage controller function that I introduced in Section 13.6.2, which involves the handling of SCSI commands received from the host via a USB client device driver channel. The le server is not involved in the processing of the commands. Instead they are processed entirely by the mass storage controller. Being a le system component, it has access to the media device concerned via the local drive interface class, TBusLocalDrive. You should note that if the drive has a le server extension mounted on it (for example a NAND drive with the ash translation layer implemented in a le server extension), then all media accesses are routed through the extension. This allows Symbian OS to support a mass storage connection to a NAND ash drive, as well as to a normal FAT drive. Only FAT-formatted drives may be connected as mass storage drives. Drives C: or Z: cannot be connected, because these must always be accessible to the rest of the OS. The mass storage le system is not normally loaded automatically during le server startup. Instead, a USB mass storage application (a component provided by the phone manufacturer) loads it later, and also mounts the le system on a particular drive. However, before it does this, the application has to dismount the FAT le system from that drive. This can only happen if there are no le or directory resources open on the drive. This may mean that the application has to request that the user shuts down certain applications that have these resources open. Once the mass storage connection is terminated, the same application is responsible for dismounting the mass storage le system and remounting the FAT le system again. Figure 13.15 shows the two con gurations of a NAND drive con gured for mass storage connection. The rst con guration shows it mounted and accessible from a Symbian OS device. The second shows it disconnected from the Symbian OS device, with a host computer accessing the drive. Granting direct access to a drive on the Symbian OS phone from a host machine poses a security threat. To counter this, all drives available for mass storage connection are subject to the same restrictions as removable drives. For instance, installed binaries on the mass storage drive could be altered while the desktop computer is remotely accessing the drive. So we need tamper evidence to detect if the contents of these binary les have been altered since they were known to be safe, at install time. Section 8.5.2.3 covers this in a little more detail.
Quick Response Code Decoder In .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
PERIPHERAL SUPPORT
Painting Bar Code In VS .NET
Using Barcode creation for VS .NET Control to generate, create barcode image in .NET applications.
A) Drive accessible from Symbian OS
Barcode Scanner In Visual Studio .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in .NET applications.
B) Drive connected as mass storage device
QR Code JIS X 0510 Encoder In Visual C#
Using Barcode creator for .NET Control to generate, create QR Code JIS X 0510 image in Visual Studio .NET applications.
2. Dismount MS on F: 3. Mount FAT on F:
Encode QR Code In .NET
Using Barcode generation for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
USB Mass Storage Application
Draw QR Code 2d Barcode In Visual Basic .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create QR Code 2d barcode image in .NET framework applications.
4. Dismount FAT on F: 5. Mount MS on F: 1. Stop MS:
EAN13 Encoder In VS .NET
Using Barcode printer for VS .NET Control to generate, create UPC - 13 image in Visual Studio .NET applications.
USB Mass Storage Application
Code 39 Full ASCII Printer In Visual Studio .NET
Using Barcode drawer for .NET framework Control to generate, create Code 3 of 9 image in VS .NET applications.
6. Start MS:
Generate UCC - 12 In .NET Framework
Using Barcode maker for .NET framework Control to generate, create UPC Symbol image in .NET framework applications.
File Server F:
Paint 2/5 Standard In VS .NET
Using Barcode drawer for Visual Studio .NET Control to generate, create Code 2/5 image in .NET framework applications.
USB Manager
Data Matrix Recognizer In Visual Studio .NET
Using Barcode scanner for .NET Control to read, scan read, scan image in VS .NET applications.
File Server F:
Encoding ANSI/AIM Code 128 In Visual C#.NET
Using Barcode generator for .NET Control to generate, create Code 128 Code Set C image in VS .NET applications.
USB Manager
Draw EAN-13 Supplement 5 In .NET Framework
Using Barcode creator for ASP.NET Control to generate, create EAN-13 Supplement 5 image in ASP.NET applications.
FAT File System
USS-128 Printer In Java
Using Barcode encoder for Java Control to generate, create UCC - 12 image in Java applications.
Mass Storage File System RDevUsbClient
ECC200 Maker In Java
Using Barcode generator for Java Control to generate, create ECC200 image in Java applications.
NAND FTL Extension
Encoding UPC-A Supplement 5 In .NET Framework
Using Barcode creation for ASP.NET Control to generate, create UPC Code image in ASP.NET applications.
NAND FTL Extension
Print Bar Code In VS .NET
Using Barcode maker for ASP.NET Control to generate, create bar code image in ASP.NET applications.
TBusLocalDrive
Read Barcode In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
TBusLocalDrive
user kernel
Local Media Sub-System
Local Media Sub-System
USB Client i/f
Host
Figure 13.15 Two con gurations of a NAND drive used for mass storage connection
Summary
In this chapter, I began by describing two more of the services available to device drivers and peripheral bus controllers: DMA and shared chunks. I went on to describe media drivers and the local media sub-system. Then I examined peripheral bus controllers looking speci cally at the MultiMediaCard controller as an example. Finally, I introduced the kernelside components of the USB software architecture and the USB mass storage le system. In the next chapter, I will describe debugging in the Symbian OS environment.