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What is "AC" with old hard disk?



 
 
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  #1  
Old April 25th 20, 11:15 PM posted to comp.sys.ibm.pc.hardware.storage
Martin Leese
external usenet poster
 
Posts: 1
Default What is "AC" with old hard disk?

Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000). On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings. These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".) What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols. This is why I am trying to
upgrade.
--
Regards,
Martin Leese
E-mail: LID
Web:
http://members.tripod.com/martin_leese/
  #2  
Old April 25th 20, 11:57 PM posted to comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default What is "AC" with old hard disk?

Martin Leese wrote:

Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000). On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings. These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".) What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols. This is why I am trying to
upgrade.


I haven't found a Maxtor HDD that says "AC" for the 2nd set of Master,
Slave, and Cable Select settings. I did find one that mentions a
secondary setting of CLJ (Cylinder Limit Jumper) which was to accomodate
old BIOSes that couldn't handle drives larger than 32 GB ... that's
really old, like over 2 decades old. That must be a really old HDD.

https://www.seagate.com/files/static...tion_guide.pdf
Page 6

Yeah, it's for a different HDD (and Seagate acquired Maxtor back in
2006), but it shows having 2 settings for each Master, Slave, and CSel
setup. I suspect the AC setting does the same.

If you don't have anything now across the AC pins, you don't need to use
that extra setting. It won't be needed in your new setup. The extra
jumper was to limit the size of the drive.
  #3  
Old April 26th 20, 01:33 AM posted to comp.sys.ibm.pc.hardware.storage
Joe Pfeiffer
external usenet poster
 
Posts: 121
Default What is "AC" with old hard disk?

Martin Leese writes:

Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000). On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings. These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".) What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols. This is why I am trying to
upgrade.


I found the manual on line, and couldn't find the settings with AC -- it
does have Slave with CLJ and Master with CLJ, however -- these are used
to tell the computer that the drive has fewer cylinders than it really
does, for *really* antique machines whose BIOS can't deal with a disk
this big. What I found is for the US market; if you're not in the US
could it be renamed for different markets?

If it were me, I'd set it to Cable Select, no CLJ.
  #4  
Old April 26th 20, 02:55 AM posted to comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default What is "AC" with old hard disk?

Joe Pfeiffer wrote:

Martin Leese writes:

Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000). On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings. These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".) What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols. This is why I am trying to
upgrade.


I found the manual on line, and couldn't find the settings with AC -- it
does have Slave with CLJ and Master with CLJ, however -- these are used
to tell the computer that the drive has fewer cylinders than it really
does, for *really* antique machines whose BIOS can't deal with a disk
this big. What I found is for the US market; if you're not in the US
could it be renamed for different markets?

If it were me, I'd set it to Cable Select, no CLJ.


Assuming you get the correct IDE connector (I think it was the one in
the middle) on the drive to make it a slave. If you're using a
one-connector cable, set the drive as Slave (since you don't want to
boot from it).
  #5  
Old April 26th 20, 02:59 AM posted to comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default What is "AC" with old hard disk?

VanguardLH wrote:

Joe Pfeiffer wrote:

Martin Leese writes:

Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000). On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings. These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".) What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols. This is why I am trying to
upgrade.


I found the manual on line, and couldn't find the settings with AC -- it
does have Slave with CLJ and Master with CLJ, however -- these are used
to tell the computer that the drive has fewer cylinders than it really
does, for *really* antique machines whose BIOS can't deal with a disk
this big. What I found is for the US market; if you're not in the US
could it be renamed for different markets?

If it were me, I'd set it to Cable Select, no CLJ.


Assuming you get the correct IDE connector (I think it was the one in
the middle) on the drive to make it a slave. If you're using a
one-connector cable, set the drive as Slave (since you don't want to
boot from it).


Well, that should've been "If you are using a 2-connector IDE cable (1
at the mobo port, 1 at the drive), set drive to Slave. If you are using
a 3-connector IDE cable (1 at mobo, 2 at the drives), use the middle
connector if you use CSEL (that's why it's called Cable Select by
deciding which connector, end or middle, to use at the drive). Or just
set the drive to Slave and don't worry to which connector you attach to
the drive."

Since the drive will be out of a computer, getting at the jumpers will
be easy. Instead of worrying about using the wrong cable connector,
setting the jumper to Slave eliminates an accidental wrong connection."
  #6  
Old April 26th 20, 07:30 PM posted to comp.sys.ibm.pc.hardware.storage
Joe Pfeiffer
external usenet poster
 
Posts: 121
Default What is "AC" with old hard disk?

VanguardLH writes:

Joe Pfeiffer wrote:

Martin Leese writes:

Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000). On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings. These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".) What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols. This is why I am trying to
upgrade.


I found the manual on line, and couldn't find the settings with AC -- it
does have Slave with CLJ and Master with CLJ, however -- these are used
to tell the computer that the drive has fewer cylinders than it really
does, for *really* antique machines whose BIOS can't deal with a disk
this big. What I found is for the US market; if you're not in the US
could it be renamed for different markets?

If it were me, I'd set it to Cable Select, no CLJ.


Assuming you get the correct IDE connector (I think it was the one in
the middle) on the drive to make it a slave. If you're using a
one-connector cable, set the drive as Slave (since you don't want to
boot from it).


You're right, of course. I assumed from the fact he wanted to make it a
Slave that he had two; were there ever cables that didn't have the
reversed wires to indicate Master/Slave?
  #7  
Old April 26th 20, 07:50 PM posted to comp.sys.ibm.pc.hardware.storage
Mark Perkins
external usenet poster
 
Posts: 110
Default What is "AC" with old hard disk?

On Sun, 26 Apr 2020 12:30:20 -0600, Joe Pfeiffer
wrote:

VanguardLH writes:

Joe Pfeiffer wrote:

Martin Leese writes:

Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000). On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings. These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".) What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols. This is why I am trying to
upgrade.

I found the manual on line, and couldn't find the settings with AC -- it
does have Slave with CLJ and Master with CLJ, however -- these are used
to tell the computer that the drive has fewer cylinders than it really
does, for *really* antique machines whose BIOS can't deal with a disk
this big. What I found is for the US market; if you're not in the US
could it be renamed for different markets?

If it were me, I'd set it to Cable Select, no CLJ.


Assuming you get the correct IDE connector (I think it was the one in
the middle) on the drive to make it a slave. If you're using a
one-connector cable, set the drive as Slave (since you don't want to
boot from it).


You're right, of course. I assumed from the fact he wanted to make it a
Slave that he had two; were there ever cables that didn't have the
reversed wires to indicate Master/Slave?


From memory, you could buy two-drive IDE cables and one-drive IDE cables.
You could also harvest a drive connector from a bad cable and install it
somewhere toward the middle of a one-drive cable to turn it into a
two-drive cable. There were also 40-pin and later 80-pin variations, so the
connector had to match.

  #8  
Old April 27th 20, 08:15 AM posted to comp.sys.ibm.pc.hardware.storage
Yousuf Khan[_2_]
external usenet poster
 
Posts: 1,296
Default What is "AC" with old hard disk?

On 4/25/2020 6:15 PM, Martin Leese wrote:
Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000).* On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings.* These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".)* What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols.* This is why I am trying to
upgrade.


I guess so far there's been no explanation of what the "AC" means yet.
My guess is that it probably stands for "Address Control" or something,
which might be a way of getting an older BIOS to understand a newer
drive. I think around this time most drives used the older CHS
(Cylinder, Head, Sector) formatting system, and to get bigger the new
generation had to switch to the newer LBA (Logical Block Address)
system. Address Control might indicate to the BIOS whether to use the
CHS system or the LBA system. Later generation BIOSes could figure this
stuff out on their own.

Yousuf Khan
  #9  
Old April 27th 20, 08:31 PM posted to comp.sys.ibm.pc.hardware.storage
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default What is "AC" with old hard disk?

Yousuf Khan wrote:

On 4/25/2020 6:15 PM, Martin Leese wrote:
Hi,

I am transferring an old hard disk (20 Gbyte
Maxtor D740X) from an old PC to a newer one
(Dell Dimension 3000).* On the old machine
the disk was the boot drive, and so was
configured as the Master device. On the newer
machine it will be a Slave device.

I have the "Jumper, CHS, and Install Guide"
for the drive, but there are two Slave
jumper settings.* These are called "Slave"
and "Slave with AC", but nowhere does the
document explain was "AC" actually is.
(There is also "Master with AC" and "Cable
Select with AC".)* What is "AC"?

I can't Google at the moment because my old
PC does not have the required encryption
protocols.* This is why I am trying to
upgrade.


I guess so far there's been no explanation of what the "AC" means yet.
My guess is that it probably stands for "Address Control" or something,
which might be a way of getting an older BIOS to understand a newer
drive. I think around this time most drives used the older CHS
(Cylinder, Head, Sector) formatting system, and to get bigger the new
generation had to switch to the newer LBA (Logical Block Address)
system. Address Control might indicate to the BIOS whether to use the
CHS system or the LBA system. Later generation BIOSes could figure this
stuff out on their own.


Even for BIOSes that supported LBA, they were and still are limited to
the number of addressing bits. At one time, 22 bits was thought
sufficient for IDE/ATA drives. Then 28 bits. Now it's up to 48 bits.
If that isn't enough for the partition size, up the entity size
(sectors). Hard disks have implemented LBA (Int13 extensions) since
1996 rather than rely on a CHS translation scheme in the BIOS.

https://en.wikipedia.org/wiki/Logica...dressing#LBA48
"The current 48-bit LBA scheme was introduced in 2003 with the ATA-6
standard,[4] raising the addressing limit to 248 512 bytes, which is
exactly 128 PiB or approximately 144.1PB."

One day, partitions will get bigger than that, and we'll need more or
different specs to address those super-sized drives. Or come up with an
entirely different addressing scheme.

The Maxtor D470X was introduced back around 1996 as part of their
redesigned DiamondMax family line using TI DSP-based architecture. That
was well back in the era when there were BIOSes with and without LBA, so
lots of drives had to cover old and new PCs at that time to maintain
their revenue. The OP wants to put that old Maxtor HDD into a Dell
Dimension 3000 the latter of which was introduced in 2004 (we don't know
what box that drive was in before). That PC will have LBA support. The
AC (aka CLJ) jumper is not needed on that old drive, because it isn't
going into a pre-millenial PC. The jumper wasn't needed in his old PC.
It won't be needed in his new[er] PC.
  #10  
Old April 29th 20, 09:07 PM posted to comp.sys.ibm.pc.hardware.storage
Yousuf Khan[_2_]
external usenet poster
 
Posts: 1,296
Default What is "AC" with old hard disk?

On 4/27/2020 3:31 PM, VanguardLH wrote:
Yousuf wrote:
I guess so far there's been no explanation of what the "AC" means yet.
My guess is that it probably stands for "Address Control" or something,
which might be a way of getting an older BIOS to understand a newer
drive. I think around this time most drives used the older CHS
(Cylinder, Head, Sector) formatting system, and to get bigger the new
generation had to switch to the newer LBA (Logical Block Address)
system. Address Control might indicate to the BIOS whether to use the
CHS system or the LBA system. Later generation BIOSes could figure this
stuff out on their own.

Even for BIOSes that supported LBA, they were and still are limited to
the number of addressing bits. At one time, 22 bits was thought
sufficient for IDE/ATA drives. Then 28 bits. Now it's up to 48 bits.
If that isn't enough for the partition size, up the entity size
(sectors). Hard disks have implemented LBA (Int13 extensions) since
1996 rather than rely on a CHS translation scheme in the BIOS.


I wasn't saying that these BIOSes couldn't understand LBA addressing,
just that they needed a manual indicator to be set, by having a jumper
switch. It would have still been early days for LBA addressing at that
point, and probably the BIOS writers couldn't be bothered to implement
self-detecting algorithms for it, so just use a jumper switch instead.

Yousuf Khan
 




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