🚀 go-pugleaf

Greetings!

Here's the deal:  I loaded MS-DOS 5.0 onto my old Zenith Z-151
(IBM-PC/XT clone).  Everything seems to work fine, except mem reports
35M of extended memory!!!!!  (the machine has 640K, no EMS, no
nothing.)  What's worse is that DOS seems to think some of it's in
use!  The obvious question:  WHY?


Booting with a plainest-vanilla floppy (no config.sys or
autoexec.bat), mem reports:

*******************************************************************************  
Conventional Memory :

  Name                Size in Decimal       Size in Hex
-------------      ---------------------   -------------
  MSDOS              55104      ( 53.8K)       D740
  COMMAND             4704      (  4.6K)       1260
  FREE              595424      (581.5K)      915E0

Total  FREE :       595424      (581.5K) 

Total bytes available to programs :                           595424   (581.5K)
Largest executable program size :                             595360   (581.4K)

  35659776 bytes total contiguous extended memory
  35651584 bytes available contiguous extended memory

*******************************************************************************  

    WOW!  The mighty Zenith's been keeping something secret all these
years!  And look, 8K are in use.  Norton 5.0 SI has no problem:

*******************************************************************************  
                             **********************
                             *   Memory Summary   *
                             **********************

              --------------------- DOS Usage ---------------------
             DOS reports 640 K-bytes of memory:
                 58 K-bytes used by DOS and resident programs
                582 K-bytes available for application programs

               --------------------- Overall ---------------------
             A search for active memory finds:
                640 K-bytes main memory      (at hex 00000-0A000)
                 32 K-bytes display memory   (at hex 0B800-0C000)
                 16 K-bytes extra memory     (at hex 0F000-0F400)
                  0 K-bytes extended memory  
                  0 K-bytes expanded memory

           --------------------- BIOS Extensions ---------------------
             ROM-BIOS Extensions are found at hex paragraphs:
             C800 

*******************************************************************************  
           
The machine is a Zenith Z-151 with a NEC V-20 at 4.77 MHz, 8087
co-processor, 640K RAM, CGA (yuk!), 2 360K floppies, and a 30M RLL
hard drive.  

Am I just going to have to wait and buy Zenith-DOS 5.0?  (Yeah, right!
3.3 is just fine, thank you.  Actually, I was previously running IBM
PC-DOS 3.3!)  If anyone's got a clue, I'd appreciate it.  As could be
expected, Microsoft is a solid busy signal.

Thanks in advance!

- Paolo -


Look ma -- no .sig!