Article 149022 of comp.os.vms:

In article <4pa95d$n8o@news9.erols.com>, dhowell@erols.com (Dave Howell) writes...
> 
>>It depends on exactly what zip and unzip did to the file.  They may have added
>>extraneous characters to the file.  If they didn't, then what you need to do is
>>to use the command (on recent enough versions of VMS)
>>	$ SET FILE/ATTRIBUTES=(RFM:FIX,MRS:32256,LRL:32256) somefile.bck
 : 
>For those of us out there who run earlier versions of VMS (5.5-2) can you
>either give us some program logic in re converting file formats a la Mr

The official way to do this is an ACP QIO. 
But if you don't tell anyone else, you can try the included RMS proggie:


#include <stdio>
#include <rms>
#include <rmedef>
main (int argc, char *argv[])
{
/* FIX_FILE.C, Hein van den Heuvel, Digital, June 1996
**
** Change (p1) input file name to RFM=FIX and LRL=MRS=(p2 = default 32256).
*/
struct FAB	fab;
int		s;

fab = cc$rms_fab;
fab.fab$b_fac = FAB$M_PUT;
fab.fab$l_fna = argv[1];
fab.fab$b_fns = STRLEN( argv[1] );
s = sys$open(&fab);
    if (!(s & 1)) return s;
fab.fab$l_ctx = RME$C_SETRFM; 
fab.fab$v_esc = 1;	
if (argc > 2) {  sscanf(argv[2], "%d", &fab.fab$w_mrs );
    } else fab.fab$w_mrs = 32256;
fab.fab$b_rfm = FAB$C_FIX;	
s=sys$modify(&fab);
    if (!(s & 1)) return s;
return sys$close(&fab);
}

And just in case it's missing from your SYS$LIBRARY, here is RMEDEF.H


#ifndef __RMEDEF_LOADED
#define __RMEDEF_LOADED	1

/*** MODULE $rmedef ***/
/*                                                                          */
/*                rms escape definitions                                    */
/*                                                                          */
/*  the following values identify various requests for non-standard rms     */
/*  functions.  they are currently input to the $modify function in the     */
/*  ctx field of the fab only if the esc bit is set in fop.  incorrect      */
/*  use of these capabilties could cause rms to fail, hence great caution   */
/*  should be exercised in their use.                                       */
/*                                                                          */
#define RME$C_SETRFM 1                  /* change rfm, mrs, and fsz (if vfc) in ifab only  */
#define RME$C_PPFECHO 2                 /* enable echo of SYS$INPUT to SYS$OUTPUT */
#define RME$C_SETRCF 3                  /* change recovery mode             */
#define RME$C_KEEP_LOCK_ON 4            /* Turn on Keep Lock behavior       */
#define RME$C_KEEP_LOCK_OFF 5           /* Turn off Keep Lock behavior      */

#endif					/* __RMEDEF_LOADED */

Hope this helps,		+--------------------------------------+
Hein van den Heuvel, Digital.	| All opinions expressed are mine, and |
  "Makers of VMS and other	| may not reflect those of my employer |
   fine Operating Systems."	+--------------------------------------+


