Amiga ISO Collection/AmigaUtilCD2.iso/Misc/vmm31.lha/VMM/doc/HISTORY

Text File | 1995-05-23 | 10.4 KB | 242 lines

$Date: 95/05/23 10:22:18 $

V1.0:  This is the first release

V1.0b: Bug fix: Unit 0 of the paging device was always used instead of the
                given unit.

       Bug fix: In case of an error "Reboot" didn't work.

V1.1:  Now runs on non-A4000 machines. Sets up its own MMU table,
       if necessary.

       Statistics window is font-sensitive now

       Dynamic memory allocation policy implemented

       Now up to 64 MB of virtual memory possible

       Now supports both 4K and 8K pages (two program versions)

       Paging to a file implemented

       Separate program for printing out statistics is available now
       ("VMM40Stat")

       Disk access time reduced.

V1.2:  Fixed a bug which caused VMM40 to crash the machine when paging to
       a file with its name longer than 20 characters.

       V1.1 tried to improve system consistency by disabling allocation of
       VM inside forbidden/disabled sections. This caused programs which
       do an AvailMem (); AllocMem () inside a Forbid/Permit to fail on
       VM allocations (e.g. ADPro). Removed in V1.2.

       A  small  program  "ShowPageSize"  has  been added to determine which
       pagesize is possible on your system.

       Maximum VM size has been increased to 128 MB as requested.

       A programmer's library has been added for exclusive use of
       virtual memory.

V1.3:  FreeMem now marks the freed pages as empty resulting in less paging
       on freeing memory. Unfortunately this breaks tools such as MungWall
       which writes to memory it hasn't allocated.

       Fixed a bug which caused strange behaviour during disk IO using
       multiple units sharing the same device. This was probably responsible
       for some strange misbehaviours when rendering text and icons.

       The preferences are now changeable while VMM40 is running.
       All parameters except the paging device/file and the page-file size
       will be immediately changed by VMM40.

       An advanced section for memory allocation has been added to
       VMM40Prefs. You can now determine the minimum size for VM allocations
       for PUBLIC and non-PUBLIC requests separately.

       Reduced VMM's usage of signals on behalf of other tasks. There were
       problems with tasks who had all their signals already allocated.

       The Wait function had to be patched in order to avoid problems
       with tasks which have a stack in VM.

       You can now exit VMM40 even if there's VM still allocated. In this
       case VMM40 will try to page in all this memory and set up the
       MMU tables accordingly, after which it will quit.

       Now writes out modified pages before it needs to resulting
       in better average page-fault service times.

       Added a reset handler which inhibits a reset until paging currently
       going on has finished. This prevents the validate procedure after
       reset if you are paging to a file.

       Fixed a bug which caused VMM40 to hang when writing the first page
       to DMA-driven harddisks.

       Some minor changes and cleanups.

V2.0:  VMM runs on the 68030. Consequently VMM40 has been renamed to VMM.

       Implemented so-called pseudo-partitions, which look like a file
       but can be accessed with the speed of a partition.

       VMM is a commodity in V2.0 using a hotkey to display its GUI.
       Consequently the setup of V2.0 has changed a bit. VMM40 has
       been moved to L:VMM-Handler and VMM40Prefs is now simply called
       VMM. The VMM: assign and the StartVMM program have become obsolete.

       Hopefully fixed bugs having to do with paging to DMA devices
       (Patched CachePreDMA and CachePostDMA)

       The GUI has changed a bit to make room for some additionally needed
       gadgets.

       VMM now patches Workbench's title bar to include the amount of free
       VM. There's a configuration button to enable or disable this feature.

       Better exit handling if there's still VM allocated.

       Miscellaneous minor changes and bug fixes

V2.0a: Fixed a small but nasty bug I introduced shortly before the release
       of V2.0 when converting from GCC 2.5.7 to GCC 2.6.0. This caused
       VMM to crash when paging to a partition was used for the first time.
       Subsequent uses of partition paging worked OK.
       Also corrected a minor mistake that caused the VMM window not to be
       updated after certain menu function were invoked.

V2.1:  AvailMem now returns amount of free public memory if task is not
       permitted to use virtual memory.

       Fixed a bug in the startup code which caused VMM to crash if the
       preferences file wasn't found. Now a requester is displayed.

       Fixed a bug in the Installer script which caused the default
       configuration file not to be copied.

       Implemented a write buffer to write multiple pages to disk.
       Although this involves copying the pages to the buffer it generally
       results in a quite noticeable speed improvement.

       Deleted the memory option for paging to the largest available chunk
       since no-one ever seems to use it.

       Paging to a file is speeded up significantly by using additional
       buffers for the filesystem. FFS and OFS are very inefficient on
       seeking on long files. VMM installs as many buffers as are needed
       to keep the file list blocks of the paging file in memory.
       Other file systems such as the MSDOS filesystem don't need this.

       FreeMem now marks the freed pages as unused instead of invalid.
       Previously subsequent accesses to that range of memory resulted
       in a page-fault without any disk access but the overhead for
       page-fault handling.

       Corrected font calculation for statistics window.

       Improved error handling.

       Fixed a hard to find bug which could cause spurious crashes on
       68030 systems with a 68882. I underestimated the amount of
       data which is pushed onto the stack during a context switch if
       the FPU is busy.

       Added support for external statistics displays. You can now write
       your own (possibly graphical) statistics output for VMM.

       Worked around a DOS bug which caused failure to use pseudo-partitions
       on partitions with the same volume and device name.

V3.0:  Implemented code paging, i.e. you can put program code into VM
       and swap it out just as usual memory.

       Implemented memory tracking. It is now possible to determine how
       much virtual memory is used by each task.

       Implemented another mode for specification of paging memory:
       The 'restricted dynamic mode' works like dynamic mode but you can
       specify lower and upper bounds for paging memory.

       I wrote a completely new user interface using MUI. This also
       supports localization.

       Hopefully fixed problems with some processor cards (Better handling
       of transparent translation registers).

       Additionally implemented a 'custom MMU setup' which should make
       all those nasty boards work which previously had problems with
       VMM's MMU setup.

       VMM can now be controlled using ARexx.

       VMM now supports machines equipped with a 68020 + 68851 combination.

       Fixed a bug which caused VMM to display a message "Not enough
       memory" when enabling statistics while VMM was running.

       Fixed a race condition which could cause VMM to crash when it
       received a message from an external statistics program during
       program exit time.

       The format of the configuration file has changed to a binary description.
       There is a program provided to convert the old style prefs file into
       the new representation.

V3.1:  Fixed   a   bug  which  caused  VMM  not  to  work  under  OS2.0.   An
       auto-OpenLibrary  'feature'  of  libnix which was unknown to me caused
       the  startup  code  to open locale.library and refuse to run if it was
       not  there.   This problem has been eliminated by simply disabling the
       auto-OpenLibrary feature.

       Added a new keyword 'FORCE' to the VMM tooltypes.  If specified in the
       icon or on the commandline, VMM will not ask you if it may overwrite a
       partition  or  file not previously used by VMM, but will simply do so.
       This  is  very useful for people who use the same paging partition for
       VMM and e.g.  LINUX.

       Raised  the  VM  limit  from 128 MB to 512 MB after receiving multiple
       requests  to  do so. Additionally the usage of physical memory for MMU
       tables has decreased a bit under certain circumstances.

       Added  a  FAST  ROM  option  to  VMM. Since on some machines there are
       problems  with  tools such as CPU which map the ROM to Fast memory and
       it wasn't much work I added this one.

       VMM is now able to create a pseudo-partition on a DC-FFS disk.

       Added  an  empty-page-collector  which causes unused pages to be freed
       more often. This reduces disk accesses due to pagefaults up to 30%.

       Fixed  a  bug in the reset code which caused VMM to generate a GURU on
       some machines when pressing reset.

       Fixed  a  minor  bug  which caused VMM to try to free memory again and
       again, although there was no memory to free.  Mostly happened when the
       system  was  short  of  CHIP  memory although VMM did not use any CHIP
       memory.

       Changed a bit in the MMU mapping when the VMM_MMU.config file is used.
       Now  memory  for  a  pagetable  is allocated on the first access to an
       address  mapped  by this table. Previously VMM could not start on some
       machines  because  their  processor boards mapped the whole 4 GB range
       needing 4 MB just for pagetables.

       Modified  the  memory  tracking such that the loadfile is displayed as
       the  owner  of  its  code and not the loading task (most important for
       libraries and devices).

       Found  a  bug  which  I  have  long  been searching for which produced
       obscure  irreproducible  crashes.   The  bug is contained in ramlib in
       conjunction with using semaphores. I have developed a patch for ramlib
       (which is not very system-conforming) which fixes this bug.

       Fixed  a  minor  bug which caused VMM to incorrectly accept partitions
       with a blocksize other than 512 bytes for pseudo-partitions.

       Worked  around a bug in GCC which caused VMM to always use the default
       settings for code paging for the compiler passes of GCC.