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Release description.
====================

Module id number: CSS/305  CSS/360  CSS/307

Module name:      ROOT ( + MEMMGR, + RTC)

Actual release:   1001            Release date: 820501
Previous release: 0901            Release date: 810801


New facilities:

>> Release 1001 <<

   Support of XAMOS.

   The RANGE field, defined in vs.0901 as part of the process
   header, must now be given to MEMMGR as word 5 of the
   ALLOCATE message.
   If this field is zero, #0F00 (page #0) is assumed for program
   allocation, and #3F00 (any page) is assumed for date allocation.
   If the field is non-zero, but the actual CPU is not an XAMOS CPU,
   program allocation is still done in page 0.
   The allocation strategy is now:
       - allocation is tried outside page 0, in the memory of the
         specified CPU
     if not successfull
       - allocation is tried in      page 0, in the memory of the
         specified CPU
     if not successfull
       - allocation is tried outside page 0, in the memory of any CPU
     if not successfull
       - allocation is tried in      page 0, in the memory of any CPU
     if not successfull
       - a bad completion code is returned
   Allocation is considered successfull, if at least one hole is
   found in the given range, from which the wanted memory can be
   allocated.  If more than one such hole is found, the smallest
   is selected.  Memory is allocated from the start of this hole.

>> Release 0901 <<

   This release is composed of the versions 0501 of the standard ROOT,
   and 0600, 0700, 0800 of the CR801 ROOT .

   Highlights :

   *    The code parts of a boot module are packed in section zero.
        This means that there is no waste of code space, from loading
        a boot module.

   *    Memory allocation is performed in chunks of 128 words.
        (In Release 0501 the chunk size was 256 words).
        This implies that the memory table occupies 2K of data
        space. (Release 0501, 1K)
        However, if there are more than 16 processes in the
        system, some space is gained.

   *    Program version numbers are output in decimal.

   *    A possibility to specify a range in which a process
        must be laid out, is implemented.
        The purpose of this facility is to help the layout
        of processes with special memory demands, e.g CDC
        Disk drivers, File System etc.
        The facility is used in the following way :
             Location 18 of a process header may define a
             range of 4K modules in which the process must
             be laid out.
             The upper byte of this location defines the top
             limit, and the lower byte defines the bottom limit.
             The range is defined as :
             Lower-byte * 4K .. ((Upper-byte + 1) * 4K) - 1
             If there is not enough free space in the range to
             lay out the process, ROOT gives the error message 3
             and terminates by loading the AMU process.

             Example :

                Location 18 of process header :

                ----------------
                | 1  7  | 1  0 |
                ----------------
                top      bottom

                This contents implies that the process must be
                laid out somewhere in the lower 32 K of memory
                section 1.

             At present the only way to insert the value into the
             process header, is to patch▶16◀▶16◀▶16◀ it.

>> Release 0501 <<
   ROOT prepared for execution outside page zero.
   RTC  process included into ROOT, and created directly by ROOT,
        so RTC module should not be used in boot modules containing this
        version of ROOT.

Changes:

>> Release 1001 <<

   The memory fill pattern is changed from #A7A7 to #E1E1, as the
   former pattern is a legal XAMOS instruction.

>> Release 0901 <<

   Some of the facilities from the CR801 versions
   have been disabled :

   *    It is not possible to disable the initial print from ROOT.

   *    Setting of baud rate to 1200 baud is disabled.

   *    The process 'FILSYS' is not forced to lie in memory
        section 3.



Errors corrected:

>> Release 0901 <<

   *    If the ROOT process was running in section one, and
        there were too many Message buffers, Process Control Blocks
        or Region Control Blocks in the system, process layout would
        terminate in error.
        This error has only been a problem to the DORA project group.

   *    When the RTC was started, it would destroy 4 locations outside
        its own process space.

   *    In the CR801 versions (0600, 0700, 0800) it was not possible
        for ROOT to layout processes in memory section zero.


>> Release 0501 <<

   RTC module : At reception of messages,
                even the global RTC is updated

Reported errors, not corrected:

Comments:
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