IS200STCIH6AED燃機(jī)模塊,GE使用進(jìn)展
內(nèi)存要求197Bug的程序部分大約是1兆字節(jié)的代碼，由下載、調(diào)試器和診斷包組成，包含完全在閃存中。MVME197LE上的閃存是從位置$FF800000開始映射。
197Bug需要至少64KB的連續(xù)讀/寫內(nèi)存運(yùn)轉(zhuǎn)ENV命令控制該內(nèi)存塊的位置。不管在板載RAM的位置中，第一個(gè)64KB用于197Bug堆棧靜態(tài)變量空間，其余保留為用戶空間。
IS200STCIH6AED燃機(jī)模塊每當(dāng)MVME197LE重置，目標(biāo)IP初始化為對應(yīng)的地址并初始化目標(biāo)堆棧指針到用戶空間內(nèi)的地址，使用目標(biāo)偽堆棧指針（R31）設(shè)置為用戶空間的頂部。終端輸入/輸出控制在提示下輸入命令時(shí)，可能會出現(xiàn)以下控制代碼：輸入以進(jìn)行有限的命令行編輯。觀察任何197Bug命令的輸出時(shí)，XON和XOFF可以輸入對終端端口有效的字符來控制如果啟用了XON/XOFF協(xié)議（默認(rèn)），則輸出。這些角色分別由197Bug初始化為^ S和^ Q，但可由用戶使用PF命令。在初始化（默認(rèn)）模式下，操作如下支持磁盤輸入/輸出197Bug可以通過與智能磁盤通信來啟動(dòng)磁盤輸入/輸出VMEbus上的控制器模塊。197Bug內(nèi)置磁盤支持設(shè)施包括命令級磁盤操作、磁盤輸入/輸出系統(tǒng)調(diào)用（僅通過一個(gè)由用戶程序使用的陷阱（496指令）和定義的數(shù)據(jù)磁盤參數(shù)的結(jié)構(gòu)。參數(shù)，例如映射模塊的地址以及類型和連接到控制器模塊的設(shè)備數(shù)量保存在表中197 UG。這些參數(shù)的默認(rèn)值在通電和冷啟動(dòng)重置，但可以按照默認(rèn)部分中的說明進(jìn)行更改參數(shù)，在本章后面。附錄B包含當(dāng)前支持的控制器列表，以及每個(gè)控制器的默認(rèn)配置列表。區(qū)塊與扇區(qū)邏輯塊定義了磁盤設(shè)備的信息單元。磁盤是197Bug將其視為劃分為邏輯塊的存儲區(qū)域。默認(rèn)情況下對于系統(tǒng)中的每個(gè)塊設(shè)備，邏輯塊大小設(shè)置為256字節(jié)。這個(gè)可以使用IOT命令在每個(gè)設(shè)備的基礎(chǔ)上更改塊大小。該部門定義了媒體本身的信息單元，由控制器。扇區(qū)大小因控制器而異，而可以使用IOT命令顯示和更改特定設(shè)備。
Memory Requirements
The program portion of 197Bug is approximately 1 megabyte of code,
consisting of download, debugger, and diagnostic packages and contained
entirely in the flash memory. The flash memory on the MVME197LE is
mapped starting at location $FF800000.
197Bug requires a minimum of 64KB of contiguous read/write memory to
operate.
The ENV command controls where this block of memory is located. Regardless
of where the onboard RAM is located, the first 64KB is used for 197Bug stack
and static variable space and the rest is reserved as user space. Whenever the
MVME197LE is reset, the target IP is initialized to the address corresponding
to the beginning of the user space, and the target stack pointers are initialized
to addresses within the user space, with the target Pseudo Stack Pointer (R31)
set to the top of the user space.Terminal Input/Output Control
When entering a command at the prompt, the following control codes may be
entered for limited command line editing.When observing output from any 197Bug 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 197Bug but may be changed by the
user using the PF command. In the initialized (default) mode, operation is as
followsDisk I/O Support
197Bug can initiate disk input/output by communicating with intelligent disk
controller modules over the VMEbus. Disk support facilities built into 197Bug
consist of command-level disk operations, disk I/O system calls (only via one
of the TRAP #496 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
197Bug. 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 197Bug 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.
