DT680B-E系统卡件，ABB使用指导
当调试固件等待各种控制器和驱动器达到速度然后开始实际的输入/输出：程序指向指定媒体的卷ID加载到RAM中，并将控制传递给它。然而，如果在此期间用户希望在没有自动启动的情况下获得控制，可以按下<BREAK>键或软件中止或重置开关。自动引导由ENV命令中包含的参数控制。这些参数允许选择特定的引导设备和文件，并允许启动延迟编程。
DT680B-E系统卡件有关详细信息，请参阅附录A中的ENV命令更多详细信息。虽然流式磁带可以用于自动引导，但相同电源必须连接到流式磁带驱动器、控制器和MVME197LE。通电时磁带控制器将流式磁带定位到加载点其中可以正确读取和使用卷ID。然而，如果MVME197LE失去电源，但控制器而磁带恰好不在加载点
所需命令序列（附加和回放）无法赋予控制器，并且自动引导将不会成功的此功能由环境（ENV）命令和在通电时（也可以在重置时）或通过RB命令执行假设闪存中有有效代码（或可选地在模块或VMEbus）来支持它。如果安装了ROMboot代码，则会为用户编写的例程提供控制（如果例程满足格式要求）。ROMboot的一个用途可能是在非智能设备上重置SYSFAIL*控制器模块。NORB命令禁用该功能。为了让用户的ROMboot模块通过ROMboot链接获得控制，
必须满足四个要求：1、必须刚刚通电（但ENV命令可以更改）这也会响应任何重置）。2、用户例程必须位于MVME197LE ROM内存中映射（但ENV命令可以将其更改为车载内存，甚至非车载VMEbus内存）。3.ASCII字符串“BOOT”必须位于指定内存中范围
4.用户的例程必须通过校验和测试，以确保例行程序实际上是为了在通电时接受控制。
有关如何使用ROMboot的完整详细信息，请参阅MVME197BUG197Bug调试包用户手册。
网络引导网络自动引导是包含在197Bug中的一个软件例程，它可以提供使用网络（本地）引导操作系统的机制
以太网接口）作为引导设备。网络自动引导例程
Following this message there is approximately a thirty-second delay while the
debug firmware waits for the various controllers and drives to come up to
speed. Then the actual I/O is begun: the program pointed to within the
volume ID of the media specified is loaded into RAM and control passed to it.
If, however, during this time the user wants to gain control without Autoboot,
the <BREAK> key or the software ABORT or RESET switches can be pressed.
Autoboot is controlled by parameters contained in the ENV command. These
parameters allow the selection of specific boot devices and files, and allow
programming of the Boot delay. Refer to the ENV command in Appendix A for
more details.Although streaming tape can be used to autoboot, the same
power supply must be connected to the streaming tape
drive, controller, and the MVME197LE. At power-up, the
tape controller will position the streaming tape to load point
where the volume ID can correctly be read and used.
If, however, the MVME197LE loses power but the controller
does not, and the tape happens not to be at load point, the
sequences of commands required (attach and rewind)
cannot be given to the controller and autoboot will not be
successful.
ROMboot
This function is configured/enabled by the Environment (ENV) command and
executed at power-up (optionally also at reset) or by the RB command
assuming there is valid code in the flash memories (or optionally elsewhere on
the module or VMEbus) to support it. If ROMboot code is installed, a userwritten routine is given control (if the routine meets the format requirements).
One use of ROMboot might be resetting SYSFAIL* on an unintelligent
controller module. The NORB command disables the function.
For a user’s ROMboot module to gain control through the ROMboot linkage,
four requirements must be met:
1. Power must have just been applied (but the ENV command can change
this to also respond to any reset).
2. The user’s routine must be located within the MVME197LE ROM memory
map (but the ENV command can change this to any other portion of the
onboard memory, or even offboard VMEbus memory).
3. The ASCII string “BOOT” must be located within the specified memory
range.
4. The user's routine must pass a checksum test, which ensures that this
routine was really intended to receive control at power-up.
For complete details on how to use ROMboot, refer to the MVME197BUG
197Bug Debugging Package User’s Manual.
Network Boot
Network Auto Boot is a software routine contained in the 197Bug that
provides a mechanism for booting an operating system using a network (local
Ethernet interface) as the boot device. The Network Auto Boot routine
