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#111887 - 12/26/17 08:44 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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rfka01 Offline
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Using those parameters, the disk boots both on my P4 that I use for imaging, and also in the MAME ct486 driver - DOS still reports 210534400 total disk storage ... maybe some trickery from the boot manager? Anyway, crazyc, thanks for steering me through this smile

[Linked Image]

[Linked Image]


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
#111888 - 12/26/17 08:58 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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crazyc Offline
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I've actually got that same model drive. My dad bought it in 1991.
[Linked Image]

#111889 - 12/26/17 09:02 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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rfka01 Offline
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The IDE cable mounts with the key down ... makes it hard to mount another drive with the original cable in the Portable 386. It would be great if you could have a look at the ROMs ... dunno what's causing the memory error.

Last edited by rfka01; 12/26/17 09:03 PM.

NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
#111890 - 12/26/17 09:19 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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Tinu Offline
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Partition one seems to be:
Code
80 010100 06 08EDF7 2D000000 2B470600


Apparently this is big endian, otherwise the LBA indicators would not make sense.

The partition starts at Cylinder 0, Head 1, Sector 1. It ends at Cylinder F7 (247), Head ED (237), Sector 08. Total disk size would be 236'096 KiB. The partition size would be 235'104 KiB. If the partition ends at the very end (which can't be seen in the MBR, I think), then the CHS values would be 248/238/8 (heads start with one, the other values with zero).

The LBA indicators show the start at 2D and the length as 6472B, which is 205'717.5 KiB. I don't know why there is such a big difference.

Partitions 2-4 are empty (all zeroes).

I do have some questions: If you can still boot the machine, can't you simply use FDISK to display the partition information?
Does CHS even matter for a CHD file? The v5 CHD format does not seem to have this information in the header anymore. Maybe the CHD parameter is just another way of specifying the total size of the virtual disk.

#111891 - 12/26/17 09:29 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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R. Belmont Offline
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C/H/S is crucial for CHD files for the current crop of PC drivers, and C/H/S metadata is very much supported in v5 CHDs.

#111892 - 12/26/17 10:04 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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rfka01 Offline
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Tinu, your CHS calculation seems to be off, but mine was too ... the two most significant bits of the sector byte make the two most significant bits of the cylinder byte, making that a 10 bit byte, if https://de.wikipedia.org/wiki/Master_Boot_Record is to be trusted.

There is definitely some trickery going on, as you can see in this screenshot from MAME, it was the same on a real machine. Different DOS versions show different information, but somehow it all boils down to a 201MB partition on a 178MB harddisk smile

[Linked Image]

Bear in mind that this is a BIOS modified to support the bigger harddisk and a customized boot manager.


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
#111893 - 12/26/17 10:57 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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Darkstar Offline
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This is an excerpt from the Seagate documentation on the ST-1239A drive:

Code
                             ST-1239A
                          94354-239 or 230  Swift

       UNFORMATTED CAPACITY (MB) ________________239
       FORMATTED CAPACITY (36 SECTORS) (MB) _____211
       ACTUATOR TYPE ____________________________VOICE COIL
       TRACKS ___________________________________11,448
       CYLINDERS ________________________________1,272
       HEADS ____________________________________9
       DISCS ____________________________________5
       MEDIA TYPE _______________________________THIN FILM
       RECORDING METHOD _________________________RLL (2,7)
       TRANSFER RATE (mbytes/sec) _______________1.25
       SPINDLE SPEED (RPM) ______________________3,600
       AVERAGE LATENCY (mSEC) ___________________8.33
       BUFFER ___________________________________32 or 64 Kbyte
         Read Look-Ahead, Non-Adaptive,
         Single-Segmented
       INTERFACE ________________________________AT BUS
       SECTORS PER DRIVE ________________________412,128
       TPI (TRACKS PER INCH) ____________________1,543
       BPI (BITS PER INCH) ______________________28,103
       AVERAGE ACCESS (ms) ______________________15
       SINGLE TRACK SEEK (ms) ___________________4
       MAX FULL SEEK (ms) _______________________35
       MTBF (power-on hours) ____________________150,000
       POWER REQUIREMENTS: +12V START-UP (amps) _2.5
                           +12V TYPICAL (amps) __0.7
                           +5V START-UP (amps) __0.75
                           +5V TYPICAL (amps) ___0.4
                           TYPICAL (watts) ______11
                           MAXIMUM (watts) ______33.75
       BUFFERED STEP PULSE RATE (micro sec) _____6-200
       WRITE PRECOMP (cyl) ______________________N/A
       REDUCED WRITE CURRENT (cyl) ______________N/A
       LANDING ZONE (cyl) _______________________AUTO PARK
       IBM AT DRIVE TYPE ________________________*

 * MAY REQUIRE FORMATTING AND PARTITIONING SOFTWARE.  ALSO, CHECK TO
SEE IF YOUR CMOS SETUP HAS A "CUSTOM" OR "USER DEFINABLE" DRIVE TYPE
AVAILABLE.

Possible Translation:  954 cyl, 12 heads, 36 sectors = 211,009,536
Possible Translation:  817 cyl, 14 heads, 36 sectors = 210,825,216
Possible Translation:  990 cyl, 16 heads, 26 sectors = 210,862,080

Note: A "custom" or "user-definded" CMOS drivetype  may ask for a
numerical value for the Write Precompensation cylinder and for the
Landing Zone cylinder.  A basic rule-of-thumb for drive models that do
not require the old Write Precomp technique or a Landing Zone because
they are Auto-Parking is to add 1 to the cylinder value being used. As
an example: If cylinders equaled 820, then both Write Precomp and
Landing Zone would be entered as 821. Some BIOS will convert this to
65535 or -1, which are functionally equivalent to "none (not used)".

#111896 - 12/27/17 08:54 AM Re: PC/XT/AT (inside) WIP topic [Re: rfka01]  
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Tinu Offline
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Originally Posted by rfka01
There is definitely some trickery going on, as you can see in this screenshot from MAME, it was the same on a real machine. Different DOS versions show different information, but somehow it all boils down to a 201MB partition on a 178MB harddisk smile

Ah yes, using the correct bits gives indeed different values wink I believe that the numbers 1015,8,45 are still slightly off, because they represent the end of the partition and not the total numbers. Because cylinder and head are zero based, the real numbers are 1016,9,45 (I believe).

With these numbers, you get a size of 210'677'760 bytes. LBA reports 210'654'720 which is probably the same: This is the partition size, not the size of the disk.

Edit: Add the LBA start of 2Dh (45 * 512 bytes) to 210'654'720 and we get indeed 210'677'760. So LBA and CHS agree 100%

Last edited by Tinu; 12/27/17 08:58 AM.
#111899 - 12/27/17 02:45 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
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Tinu Offline
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I'm not sure if this is the best thread to ask my question; It might be a generic MAME thing. Sorry if this is the case. Anyway:
In ibmpc.cpp, two hard drive controller BIOS versions are listed:
Code
5000059.bin: First version Hard drive controller ROM. Visible in memory at C8000-C9FFF.
59x7291.bin: Second version Hard drive controller ROM. Visible in memory at C8000-C8FFF.

These ROMS were physically installed on the hard disk adapter, not on the motherboard.

When I start ibm5160 with defaults, then the "hdc" adapter is loaded. From what I observe, it uses neither v1 not v2 of the BIOS: The DIP switches that select the hard disk type are ignored. No matter what I select (0-3), and no matter what hard disk image I attach, it is always treated as 615/6/17 (30MB).

So my question is: How can I select the BIOS to be used for the "hdc" adapter?

Last edited by Tinu; 12/27/17 02:58 PM.
#112104 - 01/08/18 12:44 PM Re: PC/XT/AT (inside) WIP topic [Re: solstar82]  
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Kale Offline
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Originally Posted by solstar82
its os\2 warp so i suppose its not the same crazyc tried

[Linked Image]


Not having much luck here, regressed?

[Linked Image]

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