Disk I/O Support

When observing output from any 166Bug command, the XON and XOFF characters which are in effect for the terminal port may be entered to control the output, if the XON/XOFF protocol is enabled (default). These characters are initialized to ^S and ^Q respectively by 166Bug, but you may change them with the PF command. In the initialized (default) mode, operation is as follows:

^S

(wait)

Console output is halted.

^Q

(resume)

Console output is resumed.

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Disk I/O Support

166Bug can initiate disk input/output by communicating with intelligent disk controller modules over the VMEbus. Disk support facilities built into 166Bug consist of command-level disk operations, disk I/O system calls (only via one of the TRAP #15 instructions) for use by user programs, and defined data structures for disk parameters.

Parameters such as the address where the module is mapped and the type and number of devices attached to the controller module are kept in tables by 166Bug. Default values for these parameters are assigned at power-up and cold-start reset, but may be altered as described in the section on default parameters, later in this chapter.

Appendix B contains a list of the controllers presently supported, as well as a list of the default configurations for each controller.

Blocks Versus Sectors

The logical block defines the unit of information for disk devices. A disk is viewed by 166Bug as a storage area divided into logical blocks. By default, the logical block size is set to 256 bytes for every block device in the system. The block size can be changed on a per device basis with the IOT command.

The sector defines the unit of information for the media itself, as viewed by the controller. The sector size varies for different controllers, and the value for a specific device can be displayed and changed with the IOT command.

When a disk transfer is requested, the start and size of the transfer is specified in blocks. 166Bug translates this into an equivalent sector specification, which is then passed on to the controller to initiate the transfer. If the conversion from blocks to sectors yields a fractional sector count, an error is returned and no data is transferred.

MVME166IG/D2

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Motorola MVME166D2, MVME166IG/D2 manual Disk I/O Support, Blocks Versus Sectors
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MVME166IG, MVME166D2, MVME166IG/D2 specifications

The Motorola MVME166IG/D2 is a pioneering embedded computer designed for high-performance applications in industrial and telecom sectors. This versatile computing platform is based on the PowerPC architecture, which ensures efficient processing capabilities and transfer of data, making it suitable for a wide range of applications, including real-time control, data acquisition, and system monitoring.

One of the main features of the MVME166IG/D2 is its powerful processor. The system is equipped with a PowerPC 603e processor, which offers a remarkable performance rate with a clock speed of up to 250 MHz. This high-speed processing capability allows for rapid data handling and processing, which is critical for demanding applications in real-time environments.

The MVME166IG/D2 also stands out due to its modular design. It supports multiple expansion slots that make it adaptable for different user needs. The system can accommodate additional cards or memory modules, allowing for increased versatility and capability in various operational scenarios.

In terms of connectivity, this embedded computer includes multiple communication interfaces such as Ethernet and serial ports, which facilitate seamless data transfer and communication within larger systems. This connectivity is crucial for integrating the device into existing industrial networks or for connecting with sensors and other equipment.

Another noteworthy characteristic of the MVME166IG/D2 is its robust build quality, which is essential for operation in challenging environments. The device is designed to endure high levels of shock and vibration, making it suitable for deployment in applications such as transportation or heavy machinery.

Additionally, the MVME166IG/D2 offers a range of software support which includes various real-time operating systems. This compatibility allows developers to choose the OS that best fits their application's requirements, enhancing the overall utility of the system.

In summary, the Motorola MVME166IG/D2 is a powerful, flexible embedded computing solution that excels in performance, modularity, and reliability. Its advanced features and durable design make it an ideal choice for industries that require precision, speed, and robustness in their computing solutions.
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