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From: andy@cbmvax.UUCP (Andy Finkel)
Newsgroups: comp.sys.amiga
Subject: Re: StepRate ... a utility that makes your floppies FASTER!
Message-ID: <2459@cbmvax.UUCP>
Date: Fri, 9-Oct-87 16:00:14 EDT
Article-I.D.: cbmvax.2459
Posted: Fri Oct  9 16:00:14 1987
Date-Received: Mon, 12-Oct-87 06:46:43 EDT
References: <15607@amdahl.amdahl.com>
Reply-To: andy@cbmvax.UUCP (Andy Finkel)
Organization: Commodore Technology, West Chester, PA
Lines: 224
Keywords: stepping rate improvement speedup faster floppy

In article <15607@amdahl.amdahl.com> kim@amdahl.amdahl.com (Kim DeVaughn) writes:

>The author says he can halve the access time on his drives ... down to
>about 1500 ticks (from the stock AmigaDOS* value of 3000).

Actually, I send along a C program that does this very thing, to
the moderated amiga source group awhile ago, but I guess it was during
the "time of troubles"

I did it while tracking down a bug.  First the bug...
in the file exec/devices.h a member of the Unit structure
was wrong...it should be struct  MsgPort unit_MsgPort; NOT *unit_MsgPort.

Now a warning...you can trash disks and hurt drives by using very
low values.  Check the drive mfgrs specs to be sure. We/I take
no responsibility once you start playing.

>* - I still know of no better term for the Amiga OS as a whole, than AmigaDOS;
>    especially since that's what the default CLI window is titled.

I like the term ROM KERNAL for the OS as a whole.

>To get at these parameters, you open the TrackDisk.Device and
>this device tells you where the parameters are.  Of course, the folks
>who wrote Amigados & kickstart tried to hide this parameter, so there
>isn't a name for it in the system include files.  Mr. Kegelmann found
>the right longword though.

Mr Kegelmann should have looked in the include files...there's
one with the catchy name of trackdisk.h that has the info he wanted...
ie:

	
struct TDU_PublicUnit {
        struct  Unit tdu_Unit;          /* base message port */
        UWORD   tdu_Comp01Track;        /* track for first precomp */
        UWORD   tdu_Comp10Track;        /* track for second precomp */
        UWORD   tdu_Comp11Track;        /* track for third precomp */
        ULONG   tdu_StepDelay;          /* time to wait after stepping */
        ULONG   tdu_SettleDelay;        /* time to wait after seeking */
        UBYTE   tdu_RetryCnt;           /* # of times to retry */
};


>
>The initial value of the ticks between steps (eghad, what buzzwords!)
>is set to 3000 (base 10; I mean decimal!)  by kickstart. 

Its microseconds, by the way.

Anyway, enough complaining.  Here's the program.  It also lets you
play with the settle time.


#include "exec/types.h"
#include "exec/libraries.h"
#include "exec/ports.h"

/*************************************************************
* This program allows you to read and modify the step delay
*   and settle delay times for units of the trackdisk device 
*	SetDelay 
*	by Andy Finkel
*	Copyright 1987 Commodore-Amiga, Inc.
*	Permission to distribute and use given provided
*	that this notice remains intact.
*
*   The following is a replacement for a broken include file, included
*   here for clarity 
*   Don't you do this!  Instead, fix your exec/devices.h file !
*   Change that *unit_MsgPort to a unit_MsgPort
*****************************************************************/

/*#include "exec/devices.h"*/

#define EXEC_DEVICES_H
/****** Device ******************************************************/
 
struct Device { 
    struct  Library dd_Library;
};


/****** Unit ********************************************************/

struct Unit {
    struct  MsgPort unit_MsgPort;       /* queue for unprocessed messages */
    UBYTE   unit_flags;
    UBYTE   unit_pad;
    UWORD   unit_OpenCnt;               /* number of active opens */
};


#define UNITF_ACTIVE    (1<<0)
#define UNITF_INTASK    (1<<1)

#include "exec/io.h"
#include "devices/trackdisk.h"
#include "libraries/dos.h"
#include "libraries/dosextens.h"

#define TOUPPER(c)      ((c)>='a'&&(c)<='z'?(c)-'a'+'A':(c))

struct MsgPort *trackport=NULL;
struct IOExtTD *trackreq=NULL;
struct TDU_PublicUnit *unit=NULL;
extern UBYTE *strcpy();
extern UBYTE *strcat();

main(argc,argv)
int argc;
UBYTE *argv[];
{
int unitno=0,s;
struct Process *process;
UBYTE buf[10];

    if((*argv[argc-1]=='?') || (argc < 2)) {
	printf("Usage: %ls [Unit] [Step delay] [Settle Delay]\n");
	cleanup(0);
    }
    process=(struct Process *)FindTask(NULL);

    unitno=atoi(argv[1]);
    if((unitno<0) || (unitno > 4)) {
	printf("Bad args\n");
	cleanup(10);
    }

    strcpy(buf,"df");	 /* is there the unit requested ? */
    strcat(buf,argv[1]); /* (cheap way, I know) */
    strcat(buf,":");
    process->pr_WindowPtr= (struct Window *)-1; /* quietly, please */
    s=DeviceProc(buf); 
    process->pr_WindowPtr= NULL;
    if(!s) {
	printf("Error: no unit %ld\n",unitno);
	cleanup(20);
    }

    if(!(trackport = (struct MsgPort *)CreatePort(0, 0)))cleanup(20);
    if(!(trackreq = (struct IOExtTD *)CreateExtIO(trackport,sizeof(struct IOExtTD))))cleanup(20);

    if (OpenDevice(TD_NAME, unitno, trackreq, 0))cleanup(20);

    unit= trackreq->iotd_Req.io_Unit;
    if(!unit)cleanup(20);

    if(argc >= 3) unit->tdu_StepDelay= atoi(argv[2]);
    if(argc >= 4) unit->tdu_SettleDelay= atoi(argv[3]);

    printf("step delay is %ld, settle delay is %ld\n",unit->tdu_StepDelay,unit->tdu_SettleDelay);
    cleanup(0);

}

cleanup(err)
int err;
{
    if (trackport) {
	GetMsg(trackport);
	CloseDevice(trackreq);
	DeleteExtIO(trackreq,sizeof(struct IOExtTD));
	DeletePort(trackport);
	}
    exit(err);
}

atoi( s )
char *s;
{
    int num = 0;

    while (*s && (*s == ' '))s++; /* eat leading spaces */

    if( *s == '+' ) s++;
    else if( *s == '-' ) {
        s++;
    }

    while( *s >= '0' && *s <= '9' ) {
        num = num * 10 + *s++ - '0';
    }

    while( *s >= '0' && *s <= '9' ) {
        num = num * 10 + *s++ - '0';
    }

    return( num );
}

UBYTE *
strcpy(dest, source)
UBYTE    *dest;
UBYTE    *source;
{
    UBYTE *orig = dest;
    while (*dest++ = *source++);

    return( orig );
}

UBYTE *
strcat( s, new )
UBYTE *s, *new;
{
    UBYTE c;
    UBYTE *orig = s;
    while( *s ) s++;
    do  {
        c = *s++ = *new++;
    } while( c );

    return( orig );
}
-- 
andy finkel		{ihnp4|seismo|allegra}!cbmvax!andy 
Commodore-Amiga, Inc.

"Interfere?  Of course we'll interfere.  Always do what you're best at,
 I always say."

Any expressed opinions are mine; but feel free to share.
I disclaim all responsibilities, all shapes, all sizes, all colors.