标题: PC3000中关于Program C [打印本页] 作者: 军达成 时间: 2011-8-14 16:37:59 标题: PC3000中关于Program C
为了说明什么是Program C,请允许我先引用一段来自ACE说明书中的内容,引用的文字是英文的,大家看起来不要觉得枯燥,尽管我随后将有中文解释,我也将在本文中陆续谈到Program C,但我认为语言经过转述,永远不可能与原文一致。我建议有条件的朋友还是先看原文。
4.5. Alternate service area
The manufacturer uses the alternate service area (ALT-SA) in N40P, CALYPSO and SABRE drive families.
Still, not all the N40P drives have an alternative service area. For convenience, the utility at the start logs for supporting
models a message informing the user that "HDD has an alternate service area". The presence of an alternate SA can be
identified by the PN=95h module in the module table; if module 95h is present, the drive has no alternate SA. This rule
has exceptions in N40P family because a drive with an alternate SA can be used to start a loader created from another
drive without alternate SA. In that case the module table will contain a record of module 95h; however, an attempt to
read it will demonstrate that it is empty.
The alternate service area is used during drive manufacturing for creation of the main SA and hiding of its
defects; it contains the same collection of modules, but their content differs.
The alternative program version is NCRxxxx0 in N40P or YCRxxxx0 in Calypso family; its brief representation
is "Program C". The program from the main SA is called "Program A", respectively.
In a HDD with an alternate SA, drive boot ROM after motor start reads the modules containing program code
and the translator from the main SA checking their structure. If the structure turns out to be invalid of a module cannot
be read, then loading switches to the alternate SA (see Fig. 1). A drive in that case initializes on its own using the
alternate SA. It means that switching the drive back to operation with the main SA requires recovery of its translator
and program modules. The opportunity for recording the main SA from another drive to an alternate SA is not
thoroughly studied yet. We can only make assumptions about possible results. The program in the main SA is set up to
work with its physical location despite its launch from the alternate SA. Boot ROM will run the code of program A
from the alternate SA, but the data modules will still be read from the main SA. If you start a loader with program А,
then the main SA will be linked to the UBA space; if you start it with program C, then the alternate SA will be linked
instead. There is one more difference between the A and C programs: the overlays of program A are modified during
Self Test while the overlays of program C remain the same for an identical checksum.
Microprogram С is unable to run the translator of the user zone and its adaptive modules are not suitable for
reading that zone. As a result, such drive will not be visible in LBA.
In section 4.1 we introduced the notions of: ?program 1? and ?program 2?. It is essential to understand the
difference between an alternate SA and program 2. It follows from the mechanism implemented in a drive for switching
between HDD start with program 1 or program 2 using the PN=95h module. However, in case of an alternate SA there
is no such switch. A drive switches in case of problems with the main SA.
Is there a way to switch between service areas on a functional drive? There are two methods for switching a
functional drive to the alternate SA:
1. Start an alternative loader created from the drive, when it initialized using its ALT-SA.
2. You can also switch a drive from the main to its alternate SA by enabling the ?Write all module copies?
option in the ?Utility status? dialog (Fig. 2), then modify a byte of the PN=18h module header in the module
viewing mode (Ctrl-Alt-2) and save the module.
In some drives the ?program 2? in the alternate (4.1) SA contains program A in its state prior to modification by
Self Test; it has the same ROM version as the main one, which may be useful. To start a drive using that program:
? enable the “safe mode” jumper
? start an alternative loader
? perform a ?Restart using internal HDD SA?, having selected ?program 2?.
上述的黑体字部分,就是引用的PC3000 For Windows Ver 2.20的原文说明,接下来的内容,为了理解上的方便,我不再遵循原文的结构顺序,并结合俄文的说明来讲。但我还是要强调,下面的内容,并不是上文的翻译,具体来源我不便说明,对各位有所帮助就够了。本文只在此发表,任何人无权转载,请自重。