[comp.sys.ibm.pc] 3.5 inch and 1.44 Meg

se6@cs.vu.nl (Houweling E) (04/30/88)

(YET ANOTHER) DISK PROBLEM
--------------------------
I've just installed a 3.5 inch, 1.44 Mb disk drive in a XT clone with DOS 3.2. 
The drive works all right, but FORMAT.COM formats it at just 720 Kb and 
refuses to give me the full 1.44 Meg capacity. (Yes, I used high-density disks)
The manuals gave no answers, so I'm stuck.
I wonder if maybe DOS 3.3 is needed for those high-density 3.5 disks ??
If someone knows the answer, I'd be really glad to hear it (After all, my 
reputation as 'Wizard' is at stake). 

+------------------------------------------+
| Rene' Baart                              |            
| School of Business Administration  +-------------------+
| Free University of Amsterdam       | EMAIL:            |
| Amsterdam, The Netherlands         | se6@cs.vu.nl      |
+------------------------------------| groedr@econ.vu.nl |
                                     +-------------------+

williamo@hpcupt1.HP.COM (William O'Saughnessy) (05/02/88)

The best you can do on the standard DOS 3.2 without additional programs is
to format it as a 1.2 megabyte floppy.  Even this requires a 1.2 megabyte
floppy controller.  Read the write-up on Driver.sys in the dos manual.
I am very happy to have them formatted as 1.2 meg discs;  at that capacity
they a compatible with the 5 1/4 inch 1.2 floppies and I can do disc to
disc copies.

barrett@ektools.UUCP (Chris Barrett) (05/03/88)

In article <983@tjalk.cs.vu.nl>, se6@cs.vu.nl (Houweling E) writes:
> I've just installed a 3.5 inch, 1.44 Mb disk drive in a XT clone with DOS 3.2. 
> The drive works all right, but FORMAT.COM formats it at just 720 Kb and 
> refuses to give me the full 1.44 Meg capacity. (Yes, I used high-density disks)
I had a similar problem with an IBM PC/AT.  I would allow me to format it as 
a 1.2Mb drive.  Upon investigation, it was the BIOS that was not allowing the
1.44Mb.  If your clone has the Phoenix BIOS, you might try to get a hold of
a newer version for your XT.  I have a version of the Phoenix BIOS for the 
AT that recognizes the drive fine.  Hope this helps.

Chris.

rps@homxc.UUCP (R.SHARPLES) (05/05/88)

In article <983@tjalk.cs.vu.nl>, se6@cs.vu.nl (Houweling E) writes:
> I've just installed a 3.5 inch, 1.44 Mb disk drive in a XT clone 
> with DOS 3.2. 
> The drive works all right, but FORMAT.COM formats it at just 720 Kb and 
> refuses to give me the full 1.44 Meg capacity. 
> (Yes, I used high-density disks) The manuals gave no answers, so I'm stuck.
> I wonder if maybe DOS 3.3 is needed for those high-density 3.5 disks ??

Yes, DOS 3.3 is needed.  Microsoft as well as many hardware vendors will
tell you flat out that DOS 3.2 won't support 1.4 meg format.  Some drives
come with a CONFIG.SYS device driver that will allow 1.44 meg format
but this driver generally costs $100 - $150.  For $120, DOS 3.3 is a 
better deal.

HOWEVER! You must be sure that your controller will support 1.44meg.  The
standard XT controller will not!  Just like an XT controller won't support
1.2meg 5.25" drives, it won't support 1.44meg on 3.5" drives, even if 
the disk drive will.  The controller must send a special command to the
drive to switch it into the higher density mode.  A number of companies
make disk drive controllers that support this, COPY II PC Deluxe Option Board
comes to mind, SYSGEN, Tigertronics also.

Russ Sharples
homxc!rps

NOTE:

The above in NO WAY reflects the opinions of AT&T.
These opinions are my own and the results of un-scientific and 
highly irregular analysis methods.

jimw@bucket.UUCP (Jim Willing) (05/10/88)

In article <983@tjalk.cs.vu.nl> se6@cs.vu.nl (Houweling E) writes:
>
>(YET ANOTHER) DISK PROBLEM
>--------------------------
>I've just installed a 3.5 inch, 1.44 Mb disk drive in a XT clone with DOS 3.2. 
>The drive works all right, but FORMAT.COM formats it at just 720 Kb and 
>refuses to give me the full 1.44 Meg capacity. (Yes, I used high-density disks)

Sad, but true.  To get 1.44mb storage requires a Dual-Rate controller.
XT & compatable systems (unless they are boosted QUITE a bit) can not
handle the higher xfer rate, and as such are only equipped with a "standard"
controller.

-- 

usually found at:    ..tektronix!teksce!bucket!jimw
alternatly found at  CBBS/NW (503) 284-5260
never found where you would expect him to be...

johne@hpvcla.HP.COM (John Eaton) (05/11/88)

<<<
< Sad, but true.  To get 1.44mb storage requires a Dual-Rate controller.
< XT & compatable systems (unless they are boosted QUITE a bit) can not
< handle the higher xfer rate, and as such are only equipped with a "standard"
< controller.
-- 
The transfer rate for high density is twice as much (16 vs 32 us per byte) but
it it still well below a normal hard disk transfer. If your controller has
the dual mode then you can use it.




John Eaton
!hpvcla!johne