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Conference decwet::windows-nt

Title:	Windows NT
Notice:	See note 15.0 for HCL location
Moderator:	TARKIN::LIN.com::FOLEY

Created:	Thu Oct 31 1991
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	6086
Total number of notes:	31449

6082.0. "Moving Data disks between systems/architectures?" by USPS::FPRUSS (Frank Pruss, 202-232-7347) Thu Jun 05 1997 12:53

    I heard the other day a comment that surprised me.
    
    If I heard it correctly, there it is not possible to take a data only
    NTFS disk and move it from an Intel Platform to an Alpha Platform and
    still be able to read the data.
    
    Is this true?
    
    If true, is it because there is some low level format difference
    between the platforms?  Or is it because you can't even do between one
    Intel Platform and another?
    
    I haven't quite figured out how to add a drive with either a FAT File
    System or an NTFS File system to a Fresh install of NT unless I am just
    rebuilding a configuration and have a "Saved Disk Configuration"
    preserved.

T.R	Title	User	Personal Name	Date	Lines
6082.1		DECWET::VOBA		`Thu Jun 05 1997 13:43`	7
	Re .0, hmmm... that's not true. I've done it all the time. However, there is an NTFS incompatibility between NT releases (starting at SP2, i believe) that prevents earlier NT systems (regardless of platform architecture) from seeing the disk properly. --svb
6082.2		DECWET::SCHREIBER	DECeNT	`Thu Jun 05 1997 14:18`	11
	Incorrect except for a couple of specific instances: 1) Floating point data differences between x86 and Alpha architectures. Binary data written on one architecture is not portable to the other. 2) If the disk is not dismounted cleanly (ie the system crashes), moving the disk to a system of the other architecture is problematic due to differences in the page size used to write the log file (page size = memory page size, 4KB on x86 and 8KB on Alpha). Benn
6082.3		DECWET::SCHREIBER	DECeNT	`Thu Jun 05 1997 15:02`	7
	re .2: IEEE floating point data is fully compatible. The issue only exists for Intel 80-bit FP data, which shouldn't be a big problem for most folks. Sorry for the confusion on this. Benn
6082.4		DECCXL::OUELLETTE	blackflies upgraded to mosquitos	`Thu Jun 05 1997 16:16`	4
	The 80-bit extend precision format is available from C/C++ using the long double type on x86. Using it isn't such a good idea. Most Fortran compiler for x86 don't allow REAL*10, including Visual Fortran.