Not quite - The DOS managed, and used memory area was the first 640KB
The area above that required access & management that was not part of the basic DOS software; but it could be accessed as extended memory, Expanded memory, and later by routines loaded from the pre-'command.com' loaded routines ( as specified in Config.sys, and later autoexec.bat) dos using the memory management facility associated with 'Highmem' JimB ----- Original Message ----- From: "Slattery, Tim - BLS" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, January 18, 2006 5:25 PM Subject: Re: Brief History of IBM PCs (WAS RE: Mobo caps - again!) > So why wasn't the 86 capable of accessing 1Mb ram It was. The 8086 had a 20-bit address space, which means that it could handle 1MB of RAM. DOS reserved the top 360KB of that for the OS. The lower 640KB was available to user programs. -- Tim Slattery [EMAIL PROTECTED] -- ---------------------------------------- To unsubscribe, mailto: [EMAIL PROTECTED] Is your picture included in the Official Win-Home List Members Profiles Page? http://www.besteffort.com/winhome/Profiles.html If not, write to: [EMAIL PROTECTED] -- ---------------------------------------- To unsubscribe, mailto: [EMAIL PROTECTED] Is your picture included in the Official Win-Home List Members Profiles Page? http://www.besteffort.com/winhome/Profiles.html If not, write to: [EMAIL PROTECTED]
