1747-L553控制模块，A-B产品尺寸
网络自动引导是187Bug中包含的一个软件例程提供启动操作系统机制的EPROM使用网络（本地以太网接口）作为引导设备的系统。
网络引导顺序1.Network Auto Boot例程自动扫描控制器和设备按指定顺序运行，直到找到包含引导媒体的可引导设备或列表为筋疲力尽的
1747-L553控制模块2起动。控制器扫描顺序从最低开始检测到的控制器逻辑单元号（LUN）检测到最高的LUN。（有关违约，请参阅附录CLUN。）3.通电时，启用网络引导，并提供遇到的驱动器号和控制器号有效系统控制台上显示以下消息：“正在进行网络引导…要中止hit<BREAK>”在此消息之后，有一个允许您中止的延迟如果您愿意，请参阅网络引导过程。获得控制权在没有网络引导的情况下，您可以按断开键或软件中止或重置开关。
4.然后实际输入/输出开始：程序指向将指定介质的卷ID加载到RAM中，然后控制传递给它。
网络自动引导由中包含的参数控制NIOT和ENV命令。这些参数允许选择并允许编程启动延迟。请参阅附录A中的ENV命令。
重新启动系统您可以使用三种不同的方式将系统初始化为已知状态方法：重置、中止和中断。每一个都有使在某些情况下，它比其他方法更合适。调试器具有可在事件中使用的特殊功能您的设置/操作参数已损坏或不符合健全性检查。此功能：❏ 通过按下
同时，在中止之前释放重置开关转换❏ 指示187Bug使用默认设置/操作ROM中的参数，而不是您的设置/操作NVRAM中的参数。
ROM默认值请参阅ENV命令（附录A）。
Network Auto Boot is a software routine contained in the 187Bug
EPROMs that provides a mechanism for booting an operating
system using a network (local Ethernet interface) as the boot device.
Network Boot Sequence
1. The Network Auto Boot routine automatically scans for
controllers and devices in a specified sequence until a valid
bootable device containing a boot media is found or the list is
exhausted.
2. If a valid bootable device is found, a boot from that device is
started.
The controller scanning sequence goes from the lowest
controller Logical Unit Number (LUN) detected to the
highest LUN detected. (Refer to Appendix C for default
LUNs.) 3. At powerup, Network Boot is enabled, and providing the
drive and controller numbers encountered are valid, the
following message is displayed on the system console:
"Network Boot in progress... To abort hit <BREAK>"
Following this message there is a delay to allow you to abort
the Network Boot process if you wish. To gain control
without Network Boot, you can press the BREAK key or the
software ABORT or RESET switches.
4. Then the actual I/O begins: the program pointed to within
the volume ID of the media specified is loaded into RAM and
control passed to it.
Network Auto Boot is controlled by parameters contained in the
NIOT and ENV commands. These parameters allow the selection
of specific boot devices, systems, and files, and allow programming
of the Boot delay. Refer to the ENV command in Appendix A.
Restarting the System
You can initialize the system to a known state in three different
ways: reset, abort, and break. Each has characteristics which make
it more appropriate than the others in certain situations.
The debugger has a special feature which can be used in the event
your setup/operation parameters are corrupted or do not meet a
sanity check. This feature:
❏ Is activated by pressing the RESET and ABORT switches at the
same time, and releasing the RESET switch before the ABORT
switch.
❏ Instructs 187Bug to use the default setup/operation
parameters in ROM instead of your setup/operation
parameters in NVRAM.
Refer to the ENV command (Appendix A) for the ROM defaults.
