Is there a repository for eight bit DOS and utilities?
--------------------------------------------
On Sat, 4/19/14, dmccunney <dennis.mccun...@gmail.com> wrote:

 Subject: Re: [Freedos-user] chkdsk for fat32!
 To: "Discussion and general questions about FreeDOS." 
<freedos-user@lists.sourceforge.net>
 Date: Saturday, April 19, 2014, 5:47 PM
 
 On Sat, Apr 19, 2014 at
 4:45 PM, Felix Miata <mrma...@earthlink.net>
 wrote:
 > On 2014-04-19 13:01 (GMT-0400)
 dmccunney composed:
 >
 >> Er, 486 != XT hardware.
 >
 >> I still have my
 original XT sitting on a shelf.  It has a replacement
 >> motherboard with a 10 *mhz* NEC V20
 CPU, a Hercules graphics card, and
 >>
 two Seagate ST-225 20 *MB* MFM hard drives connected to an
 add-on
 >> controller card.  (They
 pre-date IDE.)
 >
 >>
 If the target is genuine XT hardware, I'm not surprised
 if a more
 >> recent CHKDSK will fail
 to run.  Among other reasons, it's likely
 >> compiled to run on >386 CPUs, and
 simply won't execute on anything
 >> earlier.
 >
 > The XT CPU is an 8088, which, like the
 8086 from which it is derived, is a 16
 >
 bit CPU. The difference between them is the 8088 has an 8
 bit IO bus path (an
 > IBM cost reduction
 misfeature incorporated into the XT), while the 8086 has
 > 16 bit. The NEC V20 is a functional clone
 of the 8088 intended to be run at
 >
 higher clock speeds, and with claimed greater internal
 efficiency. None AFAIK
 > can possibly run
 32 bit software.
 > http://en.wikipedia.org/wiki/List_of_Intel_microprocessors#The_16-bit_processors:_MCS-86_family
 
 Correct.  The V20 featured
 improved microcode, and could actually
 execute 80186 instructions.  I had an app or
 two back when compiled
 for a 286 CPU that
 would run on the V20.
 
 Reports back then gave the V20 about 5% better
 performance than the
 8088 at the same clock
 rate, and it was a drop-in replacement, so it
 was a cheap speed up.
 
 I also had an AST 6-Pak card with a meg of
 additional RAM.  AST
 supplied software let
 me use the RAM as a disk cache and a RAMdisk.
 My startup created  a 512KB RAMdisk, and
 copied several most used
 utilities to it,
 and made the ramdisk first in my PATH, and I defined
 TEMP and TMP to point to it, for the benefit of
 things like PKZIP that
 could be told where
 to create temp files..  I also had a 256K disk
 cache.  I had a freeware app that could take
 unused video memory and
 allocate it to
 DOS.  The Hercules card left 64K free, so DOS saw a
 702K system.  The rest was seen as EMS memory,
 and reserved for things
 that could use it. 
 It sped things up a treat.
 ______
 Dennis
 https://plus.google.com/u/0/105128793974319004519
 
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