IS220PPROH1A燃机卡件,GE使用尺寸
当请求磁盘传输时，指定传输的开始和大小以块为单位。197Bug将其转换为等效的扇区规范，其中然后传递给控制器以启动传输。如果从块到扇区产生分数扇区计数，返回错误，没有传输数据。设备探针功能每当出现以下情况时，就会执行设备探测，并将条目放入设备描述符表中
访问指定设备；i、 当系统调用时
。
IS220PPROH1A燃机卡件DSKRD。DSKWR，.DSKCFIG。DSKFMT和。DSKCTRL和调试器命令BH、BO、，使用IOC、IOP、IOT、MAR和MAW。设备探测机制利用SCSI命令“Inquiry”和“模式感知”。如果指定的控制器不是SCSI，则探测器将简单返回“设备存在且未知”的状态。设备探测器进入与相关数据一起输入设备描述符表。输入后，下次完成探测时，它只返回“设备存在”状态（指向设备描述符的指针）。通过197Bug命令进行磁盘输入/输出以下197Bug命令用于磁盘输入/输出。详细信息MVME197BUG 197Bug调试中提供了它们的使用说明包装用户手册。当向特定控制器发出命令时LUN和设备LUN，197Bug会记住这些LUN，以便下一个disk命令默认使用相同的控制器和设备。IOI（输入/输出查询）IOI允许用户探测系统中所有可能的CLUN/DLUN组合并显示支持它的设备的查询数据。这个设备描述符表只有16个设备描述符的空间；用IOI命令，用户可以查看该表并在必要时将其清除。IOP（物理磁盘输入/输出）IOP允许用户读取或写入数据块，或格式化指定的设备以某种方式。IOP根据参数创建命令包由用户指定，然后调用适当的系统调用函数来执行退出操作。IOT（输入/输出示教）物联网允许用户更改任何可配置的参数和属性设备。此外，它允许用户查看系统IOC（输入/输出控制）IOC允许用户发送由特定直接控制。IOC还可用于查看生成的设备数据包使用IOP命令后。BO（引导操作系统）BO从指定设备读取操作系统或控制程序然后将控制权转移到内存中。BH（引导和暂停）BH将操作系统或控制程序从指定设备读取到内存，然后将控制返回到197Bug。它被用作调试工具。
When a disk transfer is requested, the start and size of the transfer is specified
in blocks. 197Bug 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.
Device Probe Function
A device probe with entry into the device descriptor table is done whenever a
specified device is accessed; i.e., when system calls .DSKRD, .DSKWR,
.DSKCFIG, .DSKFMT, and .DSKCTRL, and debugger commands BH, BO,
IOC, IOP, IOT, MAR, and MAW are used.
The device probe mechanism utilizes the SCSI commands “Inquiry” and
“Mode Sense”. If the specified controller is non-SCSI, the probe simply returns
a status of “device present and unknown”. The device probe makes an entry
into the device descriptor table with the pertinent data. After an entry has been made, the next time a probe is done it simply returns with “device present”
status (pointer to the device descriptor).
Disk I/O via 197Bug Commands
These following 197Bug commands are provided for disk I/O. Detailed
instructions for their use are found in the MVME197BUG 197Bug Debugging
Package User’s Manual. When a command is issued to a particular controller
LUN and device LUN, these LUNs are remembered by 197Bug so that the next
disk command defaults to use the same controller and device.
IOI (Input/Output Inquiry)
IOI allows the user to probe the system for all possible CLUN/DLUN
combinations and display inquiry data for devices which support it. The
device descriptor table only has space for 16 device descriptors; with the IOI
command, the user can view the table and clear it if necessary.
IOP (Physical Input/Output to Disk)
IOP allows the user to read or write blocks of data, or to format the specified
device in a certain way. IOP creates a command packet from the arguments
specified by the user, and then invokes the proper system call function to carry
out the operation.
IOT (Input/Output Teach)
IOT allows the user to change any configurable parameters and attributes of
the device. In addition, it allows the user to see the controllers available in the
system.
IOC (Input/Output Control)
IOC allows the user to send command packets as defined by the particular
controller directly. IOC can also be used to look at the resultant device packet
after using the IOP command.
BO (Bootstrap Operating System)
BO reads an operating system or control program from the specified device
into memory, and then transfers control to it.
BH (Bootstrap and Halt)
BH reads an operating system or control program from a specified device into
memory, and then returns control to 197Bug. It is used as a debugging tool.
