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nihilist:P



Joined: 26 May 2008
Posts: 7
nihilist:P
Hi

I am just confused about the differentpossibilities to access your HDD.
In real mode you simply use Int13h - ok fine but i work in long mode where u need another way to do so...

I read about DMA and PIO - now i got stuck.

What is the difference between DMA and PIO - there is one, right?
What is the better way (faster; most stable; most common)?
Are there other ways?

Greetings and thanx
Post 26 May 2008, 17:42
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
NOTE: THE BELOW CODE WILL OVER WRITE YOUR MBR, so do not run with below settings.
To read/write to hdd is very easy, but it's the fat that will take more time, to get right.
Code:
;       Reading the harddisk using ports!;       +-------------------------------+   by qark;;;  This took me months to get working but I finally managed it.;;  This code only works for the 286+ so you must detect for 8088's somewhere;  in your code.;;  Technical Information on the ports:;      Port    Read/Write   Misc;     ------  ------------ -------------------------------------------------;       1f0       r/w       data register, the bytes are written/read here;       1f1       r         error register  (look these values up yourself);       1f2       r/w       sector count, how many sectors to read/write;       1f3       r/w       sector number, the actual sector wanted;       1f4       r/w       cylinder low, cylinders is 0-1024;       1f5       r/w       cylinder high, this makes up the rest of the 1024;       1f6       r/w       drive/head;                              bit 7 = 1;                              bit 6 = 0;                              bit 5 = 1;                              bit 4 = 0  drive 0 select;                                    = 1  drive 1 select;                              bit 3-0    head select bits;       1f7       r         status register;                              bit 7 = 1  controller is executing a command;                              bit 6 = 1  drive is ready;                              bit 5 = 1  write fault;                              bit 4 = 1  seek complete;                              bit 3 = 1  sector buffer requires servicing;                              bit 2 = 1  disk data read corrected;                              bit 1 = 1  index - set to 1 each revolution;                              bit 0 = 1  previous command ended in an error;       1f7       w         command register;                            commands:;                              50h format track;                              20h read sectors with retry;                              21h read sectors without retry;                              22h read long with retry;                              23h read long without retry;                              30h write sectors with retry;                              31h write sectors without retry;                              32h write long with retry;                              33h write long without retry;;  Most of these should work on even non-IDE hard disks.;  This code is for reading, the code for writing is the next article.    mov     dx,1f6h         ;Drive and head port  mov     al,0a0h         ;Drive 0, head 0      out     dx,al       mov     dx,1f2h         ;Sector count port    mov     al,1            ;Read one sector      out     dx,al       mov     dx,1f3h         ;Sector number port   mov     al,1            ;Read sector one      out     dx,al       mov     dx,1f4h         ;Cylinder low port    mov     al,0            ;Cylinder 0   out     dx,al       mov     dx,1f5h         ;Cylinder high port   mov     al,0            ;The rest of the cylinder 0   out     dx,al       mov     dx,1f7h         ;Command port mov     al,20h          ;Read with retry.     out     dx,alstill_going:       in      al,dx test    al,8            ;This means the sector buffer requires                                ;servicing.   jz      still_going     ;Don't continue until the sector buffer                              ;is ready.  mov     cx,512/2        ;One sector /2        mov     di,offset buffer      mov     dx,1f0h         ;Data port - data comes in and out of here.   rep     insw;   ------  mov     ax,201h         ;Read using int13h then compare buffers.      mov     dx,80h        mov     cx,1  mov     bx,offset buffer2     int     13h mov     cx,512        mov     si,offset buffer      mov     di,offset buffer2     repe    cmpsb jne     failure       mov     ah,9  mov     dx,offset readmsg     int     21h   jmp     good_exitfailure:       mov     ah,9  mov     dx,offset failmsg     int     21hgood_exit:   mov     ax,4c00h        ;Exit the program     int     21h readmsg db      'The buffers match.  Hard disk read using ports.$'  failmsg db      'The buffers do not match.$'buffer  db      512 dup ('V')buffer2 db      512 dup ('L');;       Writing to the hard disk using the ports!     by qark;       +---------------------------------------+;;  The only differences between reading and writing using the ports is;  that 30h is sent to the command register, and instead of INSW you;  OUTSW.  ;  mov     dx,1f6h         ;Drive and head port  mov     al,0a0h         ;Drive 0, head 0      out     dx,al       mov     dx,1f2h         ;Sector count port    mov     al,1            ;Write one sector     out     dx,al       mov     dx,1f3h         ;Sector number port   mov     al,1           ;Wrote to sector one   out     dx,al       mov     dx,1f4h         ;Cylinder low port    mov     al,0            ;Cylinder 0   out     dx,al       mov     dx,1f5h         ;Cylinder high port   mov     al,0            ;The rest of the cylinder 0   out     dx,al       mov     dx,1f7h         ;Command port mov     al,30h          ;Write with retry.    out     dx,aloogle:     in      al,dx test    al,8            ;Wait for sector buffer ready.        jz      oogle       mov     cx,512/2        ;One sector /2        mov     si,offset buffer      mov     dx,1f0h         ;Data port - data comes in and out of here.   rep     outsw           ;Send it.;    ------------      mov     ax,201h                 ;We'll read in sector 1 using        mov     bx,offset buffer2       ;int13h and see if we are successful. mov     cx,1  mov     dx,80h        int     13h mov     cx,512        mov     si,offset buffer      mov     di,offset buffer2     repe    cmpsb                   ;Compare the buffers. jne     failure     mov     ah,9  mov     dx,offset write_msg   int     21h   jmp     w_exitfailure:  mov     ah,9  mov     dx,offset fail        int     21hw_exit:    mov     ax,4c00h        ;Exit the program     int     21h write_msg       db      'Sector one written to using the ports, OH NO! there goes XP.$'     fail            db      'Writing using ports failed.$'buffer  db      512 dup ('A')buffer2 db      512 dup ('D')    

NOTE: THE ABOVE CODE WILL OVER WRITE YOUR MBR, so do not run with above settings.
Post 26 May 2008, 19:11
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nihilist:P



Joined: 26 May 2008
Posts: 7
nihilist:P
Thank you very much... one more question:

Does that use PIO, right?

What is today the most common way? Is DMA out???
Post 26 May 2008, 19:24
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nihilist:P



Joined: 26 May 2008
Posts: 7
nihilist:P
That is what I found there...
(Windows offers the option to enable the "good" DMA-mode.)

After Reading this:

http://www.osdev.org/wiki/DMA

Quote:

This register really shows how incompatible the 8237 is with the PC hardware. Let's start with EXTW and COMP. These increase the speed of DMA transfer by 25% be removing one of the clock cycles. Does it work? No. PRIO. When zeroed, this allows DMA priorities to be rotated allowing freedom and liberty for all peripherals that share the data bus. Does it work? No. MMT and ADHE. Did you know that the IBM PC could do memory to memory transfers since 1981? Thats right, hardware sprites, hardware frame buffering from one location to another. Does it work? No. COND. Hooray the only bit in the control register that does something useful. Setting this bit disables the DMA controller. This lets you set up multiple DMA channels without masking each and every channel.


Is that the same DMA??? rofl - nice job then INTEL
Post 26 May 2008, 19:29
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
Post 26 May 2008, 20:20
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StarKnightD



Joined: 04 Jul 2007
Posts: 38
StarKnightD
Hi,

I'm looking to code a HDD scanning program that works at boot time to determine which sectors are faulty.. I would like to be able to recover this information and black list the sectors in question. as long as I don't defrag the drive, I don't see how I need anything except a folder whose "files" are the damaged sectors.

That aside, my first priority is actually using the BIOS or IO ports to access the drive, but I don't know how the "geometry" works as far as the BIOS is concerned, and I'm not sure about IO ports since, technically, it's a SATA drive.

Would someone point me in the right direction as to programming this thing? first and foremost, I'm looking to diagnose the hard drives I have.. I finally bought a 500gb and the thing went bad.. nearly a year later I buy a second 500gb to replace it and it goes bad within days of the 30-day warranty running out. I have more storage capacity in these 2 things than I have in my other drives combined and I'm certainly not in the mood to buy another one (even if I could).

The following text was rendered by Windows XP64 from within whatever progam pops open when an "nfo" file is opened (don't remember right now)..


[Hardware Resources]



[Conflicts/Sharing]

Resource Device
I/O Port 0x00000000-0x000003AF PCI bus
I/O Port 0x00000000-0x000003AF Direct memory access controller

I/O Port 0x000003C0-0x000003DF PCI standard PCI-to-PCI bridge
I/O Port 0x000003C0-0x000003DF Radeon X1600 Series

IRQ 20 Realtek AC'97 Audio
IRQ 20 NVIDIA nForce4 Serial ATA Controller
IRQ 20 NVIDIA Network Bus Enumerator

I/O Port 0x00009000-0x0000FFFF PCI bus
I/O Port 0x00009000-0x0000FFFF PCI standard PCI-to-PCI bridge

Memory Address 0xD0000000-0xFEBFFFFF PCI bus
Memory Address 0xD0000000-0xFEBFFFFF PCI standard PCI-to-PCI bridge
Memory Address 0xD0000000-0xFEBFFFFF Radeon X1600 Series

IRQ 19 VIA Rev 5 or later USB Universal Host Controller
IRQ 19 VIA OHCI Compliant IEEE 1394 Host Controller

Memory Address 0xA0000-0xBFFFF PCI bus
Memory Address 0xA0000-0xBFFFF PCI standard PCI-to-PCI bridge
Memory Address 0xA0000-0xBFFFF Radeon X1600 Series

I/O Port 0x000003B0-0x000003DF PCI bus
I/O Port 0x000003B0-0x000003DF PCI standard PCI-to-PCI bridge
I/O Port 0x000003B0-0x000003DF Radeon X1600 Series


[DMA]

Resource Device Status
Channel 4 Direct memory access controller OK
Channel 2 Standard floppy disk controller OK

[Forced Hardware]

Device PNP Device ID

[I/O]

Resource Device Status
0x00000000-0x000003AF PCI bus OK
0x00000000-0x000003AF Direct memory access controller OK
0x000003B0-0x000003DF PCI bus OK
0x000003B0-0x000003DF PCI standard PCI-to-PCI bridge OK
0x000003B0-0x000003DF Radeon X1600 Series OK
0x000003E0-0x00000CF7 PCI bus OK
0x00009000-0x0000FFFF PCI bus OK
0x00009000-0x0000FFFF PCI standard PCI-to-PCI bridge OK
0x0000FF00-0x0000FF1F NVIDIA nForce PCI System Management OK
0x00004C00-0x00004C3F NVIDIA nForce PCI System Management OK
0x00004C40-0x00004C7F NVIDIA nForce PCI System Management OK
0x0000EA00-0x0000EAFF Realtek AC'97 Audio OK
0x0000EE00-0x0000EEFF Realtek AC'97 Audio OK
0x0000FB00-0x0000FB0F NVIDIA nForce4 Parallel ATA Controller OK
0x000001F0-0x000001F7 NVIDIA nForce4 Parallel ATA Controller OK
0x000003F6-0x000003F6 NVIDIA nForce4 Parallel ATA Controller OK
0x00000170-0x00000177 NVIDIA nForce4 Parallel ATA Controller OK
0x00000376-0x00000376 NVIDIA nForce4 Parallel ATA Controller OK
0x000009F0-0x000009F7 NVIDIA nForce4 Serial ATA Controller OK
0x00000BF0-0x00000BF3 NVIDIA nForce4 Serial ATA Controller OK
0x00000970-0x00000977 NVIDIA nForce4 Serial ATA Controller OK
0x00000B70-0x00000B73 NVIDIA nForce4 Serial ATA Controller OK
0x0000F600-0x0000F60F NVIDIA nForce4 Serial ATA Controller OK
0x000009E0-0x000009E7 NVIDIA nForce4 Serial ATA Controller OK
0x00000BE0-0x00000BE3 NVIDIA nForce4 Serial ATA Controller OK
0x00000960-0x00000967 NVIDIA nForce4 Serial ATA Controller OK
0x00000B60-0x00000B63 NVIDIA nForce4 Serial ATA Controller OK
0x0000F100-0x0000F10F NVIDIA nForce4 Serial ATA Controller OK
0x0000DF00-0x0000DF1F VIA Rev 5 or later USB Universal Host Controller OK
0x0000DE00-0x0000DE1F VIA Rev 5 or later USB Universal Host Controller OK
0x0000DD00-0x0000DD7F VIA OHCI Compliant IEEE 1394 Host Controller OK
0x0000F000-0x0000F007 NVIDIA Network Bus Enumerator OK
0x0000C000-0x0000CFFF PCI standard PCI-to-PCI bridge OK
0x0000B000-0x0000BFFF PCI standard PCI-to-PCI bridge OK
0x0000A000-0x0000AFFF PCI standard PCI-to-PCI bridge OK
0x000003C0-0x000003DF PCI standard PCI-to-PCI bridge OK
0x000003C0-0x000003DF Radeon X1600 Series OK
0x00009E00-0x00009EFF Radeon X1600 Series OK
0x00004000-0x0000407F Motherboard resources OK
0x00004080-0x000040FF Motherboard resources OK
0x00004400-0x0000447F Motherboard resources OK
0x00004480-0x000044FF Motherboard resources OK
0x00004800-0x0000487F Motherboard resources OK
0x00004880-0x000048FF Motherboard resources OK
0x00000010-0x0000001F Motherboard resources OK
0x00000022-0x0000003F Motherboard resources OK
0x00000044-0x0000005F Motherboard resources OK
0x00000062-0x00000063 Motherboard resources OK
0x00000065-0x0000006F Motherboard resources OK
0x00000074-0x0000007F Motherboard resources OK
0x00000091-0x00000093 Motherboard resources OK
0x000000A2-0x000000BF Motherboard resources OK
0x000000E0-0x000000EF Motherboard resources OK
0x00000B78-0x00000B7B Motherboard resources OK
0x00000F78-0x00000F7B Motherboard resources OK
0x00000A78-0x00000A7B Motherboard resources OK
0x00000E78-0x00000E7B Motherboard resources OK
0x00000BBC-0x00000BBF Motherboard resources OK
0x00000FBC-0x00000FBF Motherboard resources OK
0x000004D0-0x000004D1 Motherboard resources OK
0x00000290-0x0000030F Motherboard resources OK
0x00000020-0x00000021 Programmable interrupt controller OK
0x000000A0-0x000000A1 Programmable interrupt controller OK
0x00000080-0x00000090 Direct memory access controller OK
0x00000094-0x0000009F Direct memory access controller OK
0x000000C0-0x000000DF Direct memory access controller OK
0x00000040-0x00000043 System timer OK
0x00000070-0x00000073 System CMOS/real time clock OK
0x00000061-0x00000061 System speaker OK
0x000000F0-0x000000FF Numeric data processor OK
0x000003F0-0x000003F5 Standard floppy disk controller OK
0x000003F7-0x000003F7 Standard floppy disk controller OK
0x000003F8-0x000003FF Communications Port (COM1) OK
0x000002F8-0x000002FF Communications Port (COM2) OK
0x00000378-0x0000037F Printer Port (LPT1) OK
0x00000778-0x0000077B Printer Port (LPT1) OK
0x00000060-0x00000060 Standard 101/102-Key or Microsoft Natural PS/2 Keyboard OK
0x00000064-0x00000064 Standard 101/102-Key or Microsoft Natural PS/2 Keyboard OK

[IRQs]

Resource Device Status
IRQ 9 Microsoft ACPI-Compliant System OK
IRQ 12 NVIDIA nForce PCI System Management OK
IRQ 22 Standard OpenHCD USB Host Controller OK
IRQ 23 Standard Enhanced PCI to USB Host Controller OK
IRQ 20 Realtek AC'97 Audio OK
IRQ 20 NVIDIA nForce4 Serial ATA Controller OK
IRQ 20 NVIDIA Network Bus Enumerator OK
IRQ 14 NVIDIA nForce4 Parallel ATA Controller OK
IRQ 15 NVIDIA nForce4 Parallel ATA Controller OK
IRQ 21 NVIDIA nForce4 Serial ATA Controller OK
IRQ 19 VIA Rev 5 or later USB Universal Host Controller OK
IRQ 19 VIA OHCI Compliant IEEE 1394 Host Controller OK
IRQ 16 VIA Rev 5 or later USB Universal Host Controller OK
IRQ 17 VIA USB Enhanced Host Controller OK
IRQ 18 Radeon X1600 Series OK
IRQ 0 System timer OK
IRQ 8 System CMOS/real time clock OK
IRQ 13 Numeric data processor OK
IRQ 6 Standard floppy disk controller OK
IRQ 4 Communications Port (COM1) OK
IRQ 3 Communications Port (COM2) OK
IRQ 1 Standard 101/102-Key or Microsoft Natural PS/2 Keyboard OK

[Memory]

Resource Device Status
0xA0000-0xBFFFF PCI bus OK
0xA0000-0xBFFFF PCI standard PCI-to-PCI bridge OK
0xA0000-0xBFFFF Radeon X1600 Series OK
0xD0000000-0xFEBFFFFF PCI bus OK
0xD0000000-0xFEBFFFFF PCI standard PCI-to-PCI bridge OK
0xD0000000-0xFEBFFFFF Radeon X1600 Series OK
0xFEBFF000-0xFEBFFFFF Standard OpenHCD USB Host Controller OK
0xFEBFE000-0xFEBFE0FF Standard Enhanced PCI to USB Host Controller OK
0xFEBFD000-0xFEBFDFFF Realtek AC'97 Audio OK
0xFEBFB000-0xFEBFBFFF NVIDIA nForce4 Serial ATA Controller OK
0xFEBFA000-0xFEBFAFFF NVIDIA nForce4 Serial ATA Controller OK
0xFE9FF000-0xFE9FF0FF VIA USB Enhanced Host Controller OK
0xFE9FE000-0xFE9FE7FF VIA OHCI Compliant IEEE 1394 Host Controller OK
0xFEBF9000-0xFEBF9FFF NVIDIA Network Bus Enumerator OK
0xFE800000-0xFE8FFFFF PCI standard PCI-to-PCI bridge OK
0xFE700000-0xFE7FFFFF PCI standard PCI-to-PCI bridge OK
0xFE600000-0xFE6FFFFF PCI standard PCI-to-PCI bridge OK
0xFE500000-0xFE5FFFFF PCI standard PCI-to-PCI bridge OK
0xFE400000-0xFE4FFFFF PCI standard PCI-to-PCI bridge OK
0xFE300000-0xFE3FFFFF PCI standard PCI-to-PCI bridge OK
0xFE200000-0xFE2FFFFF PCI standard PCI-to-PCI bridge OK
0xFE2F0000-0xFE2FFFFF Radeon X1600 Series OK
0xFE2E0000-0xFE2EFFFF Radeon X1600 Series Secondary OK
0xE0000000-0xEFFFFFFF Motherboard resources OK
0xF0000-0xF3FFF System board OK
0xF4000-0xF7FFF System board OK
0xF8000-0xFBFFF System board OK
0xFC000-0xFFFFF System board OK
0x3FFF0000-0x3FFFFFFF System board OK
0xFFFF0000-0xFFFFFFFF System board OK
0x0000-0x9FFFF System board OK
0x100000-0x3FFEFFFF System board OK
0xFEC00000-0xFEC00FFF System board OK
0xFEE00000-0xFEEFFFFF System board OK
0xFEFFF000-0xFEFFFFFF System board OK
0xFFF80000-0xFFF80FFF System board OK
0xFFF90000-0xFFFBFFFF System board OK
0xFFFED000-0xFFFEFFFF System board OK
Post 13 Sep 2008, 07:30
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sinsi



Joined: 10 Aug 2007
Posts: 695
Location: Adelaide
sinsi
Just use chkdsk
Post 13 Sep 2008, 07:45
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17327
Location: In your JS exploiting you and your system
revolution
Yes, chkdsk, or even spinrite for a more thorough analysis.

But if you want to "roll your own" then I recommend you use the BIOS INT 13h interface. It is simple and easy to use without the concern about ports and I/O controllers etc.

[edit]changed to INT 13h[/edit]


Last edited by revolution on 13 Sep 2008, 09:52; edited 1 time in total
Post 13 Sep 2008, 08:20
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sinsi



Joined: 10 Aug 2007
Posts: 695
Location: Adelaide
sinsi
revolution wrote:
use the BIOS INT 10h interface.

INT 13h maybe? Smile
Post 13 Sep 2008, 09:42
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17327
Location: In your JS exploiting you and your system
revolution
sinsi wrote:
revolution wrote:
use the BIOS INT 10h interface.

INT 13h maybe? Smile
Embarassed Thanks.
Post 13 Sep 2008, 09:51
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neville



Joined: 13 Jul 2008
Posts: 507
Location: New Zealand
neville
Dex4u wrote:
Quote:
buffer2 db 512 dup ("D")

What sort of weird code is this?
We don't DUP around here laddie, we TIMES Wink

OK, so the (MASM) code will work for legacy CHS access up to 1024cyl x 63s x 16h x 512b = 500Mb or so.

But nihilist's disks are 500Gb. Have you got any code for absolute 32-bit sector / "LBA" access ?

_________________
FAMOS - the first memory operating system
Post 13 Sep 2008, 09:57
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StarKnightD



Joined: 04 Jul 2007
Posts: 38
StarKnightD
Quote:

But nihilist's disks are 500Gb.


I think you're referring to me.. and no, I'm trying to find info on absolute addressing..

Quote:

Just use chkdsk


doesn't work, already tried it.. one drive has mechanical problems, the other one doesn't wanna be helped by chkdsk.. I ran chkdsk and it still keeps my OS from booting.

as far as the one with mechanical problems go, I'd like to isolate the sectors which cause it.. I think one of the heads are damaged.
Post 13 Sep 2008, 10:35
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edfed



Joined: 20 Feb 2006
Posts: 4240
Location: 2018
edfed
Quote:
got any code for absolute 32-bit sector / "LBA" access ?


there is no 32 bits LBA addresses.

only LBA 28 and LBA 48
FAT32 is FAT28

first, following the docs, you should select the drive.
master? slave?
read it's feature, driveID 0Eh
after, set it's mode.

but... just take a look at this
old news are good also.

with LBA28, you can theorically access up to 2^28*2^9 = 2^37 bytes.
128 Gigabytes.


Last edited by edfed on 11 Sep 2009, 22:55; edited 2 times in total
Post 13 Sep 2008, 11:16
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4633
Location: Argentina
LocoDelAssembly
IBM/MS INT 13 Extensions - EXTENDED READ (Read the others of the family too)

According to what SpinRite's author says it is advisable to disable S.M.A.R.T. before trying to recover data on damaged sectors because otherwise the HDD logic will replace them with spare sectors making the damaged one unnacessible for ever (not counting special equipment that could exist to do raw reading of the surface of course).

Those HDDs were Western Digital?

Quote:

We don't DUP around here laddie, we TIMES

fasm supports dup and it is faster than times but yet dup is very slow Confused

Code:
; Tests on AMD Athlon64 2.0 GHz using FASMW 1.67.27

; 0.1 seconds
rb 1024*1024*10 - 1
db 0

; 1.0-1.1 seconds
times 1024*1024*10 db 0

; 0.6 seconds
db 1024*1024*10 dup (0)    
Post 13 Sep 2008, 11:20
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edfed



Joined: 20 Feb 2006
Posts: 4240
Location: 2018
edfed
Quote:
fasm supports dup and it is faster than times but yet dup is very slow


Code:
; Tests on AMD Athlon64 2.0 GHz using FASMW 1.67.27

; 0.1 second
rb 1024*1024*10 - 1
db 0

; 1.0-1.1 seconds
times 1024*1024*10 db 0

; 0.6 seconds
db 1024*1024*10 dup (0)




no comment.

apparentlly, fasm is optimised for RISC assembly.

PIII mobile @ 800MHz

; 0.4 second
rb 1024*1024*10 - 1
db 0

; 3.2 seconds
times 1024*1024*10 db 0

; 2.4 seconds
db 1024*1024*10 dup (0)
Post 13 Sep 2008, 11:33
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StarKnightD



Joined: 04 Jul 2007
Posts: 38
StarKnightD
Quote:

Those HDDs were Western Digital?

one drive is a Samsung HD501LJ
the other one is Seagate ST3500630AS

Quote:

IBM/MS INT 13 Extensions - EXTENDED READ (Read the others of the family too)

I will! Thanks!
Post 13 Sep 2008, 12:53
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
neville wrote:
Dex4u wrote:
Quote:
buffer2 db 512 dup ("D")

What sort of weird code is this?
We don't DUP around here laddie, we TIMES Wink

OK, so the (MASM) code will work for legacy CHS access up to 1024cyl x 63s x 16h x 512b = 500Mb or so.

But nihilist's disks are 500Gb. Have you got any code for absolute 32-bit sector / "LBA" access ?


As well as what's been posted above, i did not write it, if you read the code it say
Quote:

; +-------------------------------+ by qark
Post 13 Sep 2008, 15:08
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neville



Joined: 13 Jul 2008
Posts: 507
Location: New Zealand
neville
Dex, no explanation required, it was just my poor attempt at some humour

StarKnightD, sorry didn't see you Confused

edfed, I agree, but also there are 32-bit absolute sectors. For example, in every HD partition table. And of course in INT13h EDD BIOS extensions.

LocoDelAssembly, thanx, I wonder when FASM started supporting dup? I've never used FASMW, and at least up to DOS version 1.51 (2004) it's not supported and after converting all dup's to the times syntax I've never tried dup again. I just checked and FASM 1.66 for DOS does support dup.

revolution, getting back to nihilist's first question, is it possible to use INT 13h in long mode after all? (I must get myself a 64-bit machine one day so I can find out for myself Smile )

_________________
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Post 13 Sep 2008, 20:08
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17327
Location: In your JS exploiting you and your system
revolution
neville wrote:
revolution, getting back to nihilist's first question, is it possible to use INT 13h in long mode after all?
(Assuming you mean using the BIOS INT13h code)

Short answer: Yes

Long answer: Yes, but you will need a 16bit emulator environment. Not so simple to implement properly.
Post 13 Sep 2008, 23:36
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neville



Joined: 13 Jul 2008
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neville
So how can large disks be accessed in long mode, using ports and controllers? Confused

_________________
FAMOS - the first memory operating system
Post 14 Sep 2008, 04:40
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