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oldlinux-files/docs/interrupts/int-html0/inte70og.htm
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<title>INT 13,A - Read Long Sector (XT &amp; newer)</title>
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<h1><a name="kap_interrupt_0500"></a>INT 13,A - Read Long Sector
(XT &amp; newer)</h1>
<p> AH = 0A</p>
<p> AL = number of sectors (1-121 dec.)</p>
<p> CH = track number (0-1023 dec., see below)</p>
<p> CL = sector number (1-17 dec., see below)</p>
<p> DH = head number (0-15 dec.)</p>
<p> DL = fixed drive number (80h=drive 0, 81h=drive 1)</p>
<p> ES:BX = address of buffer</p>
<p> on return:</p>
<p> AH = status (see ~INT 13,STATUS~)</p>
<p> AL = number of sectors actually transferred</p>
<p> CF = 0 if successful</p>
<p> = 1 if error</p>
<p> - BIOS disk reads should be retried at least three times and
the</p>
<p> controller should be reset upon error detection</p>
<p> - many good programming references indicate this function is
only</p>
<p> available on the AT, PS/2 and later systems, but all hard
disk</p>
<p> systems since the XT have this function available</p>
<p> - reads regular data sectors (128-1024 bytes) with an
additional</p>
<p> 4 byte ECC code included</p>
<p> - a DMA boundary error will occur if the buffer at ES:BX
crosses</p>
<p> a 64K segment boundary</p>
<p> - only the disk number is checked for validity</p>
<p> - the parameters in CX change depending on the number of
cylinders;</p>
<p> the track/cylinder number is a 10 bit value taken from the 2
high</p>
<p> order bits of CL and the 8 bits in CH (low order 8 bits of
track):</p>
<p> ¦F¦E¦D¦C¦B¦A¦9¦8¦7¦6¦5¦4¦3¦2¦1¦0¦ CX</p>
<p> ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ +-------------- sector number</p>
<p> ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ +-------------- high order 2 bits of
track number</p>
<p> +-------------------------- low order 8 bits of track number</p>
<p> - see ~INT 13,2~</p>
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<td width="33%">Zurück zum <a href="inte1at0.htm">Interrupt
Info</a>. </td>
<td align="center" width="33%"><a
href="mailto:Roger.Morgan@htl-steyr.ac.at">Roger Morgan</a>
/ 1998 </td>
<td align="right" width="33%"><font size="1">L.Änderung <!--webbot
bot="Timestamp" s-type="EDITED" s-format="%d.%m.%y"
startspan -->29.03.99<!--webbot bot="Timestamp" endspan
i-checksum="13964" --> </font></td>
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