Mac OS X doesn't see the encrypted partitions on my external SATA HDD when using different adapter/controllers?

The drive is using "4K native" sectors (instead of 512 bytes per sector,
or 4K per sector with 512-byte emulation) and the Vantec adapter is the
only one of the three which supports this. As a result, the other
adapters are misreading the volume (reading the first 512 bytes out of
every 4K sector, and discarding the rest).

This happens to allow reading the protective/legacy MBR at the start of
the GUID partition table, but the rest of the GUID partition table is
missing. Note the "Content: 0xEE" which is also consistent with GUID
Partition Table: the protective MBR contains what looks like a single
partition occupying the entire drive, with a partition type of 0xEE.

A related clue is that the partition size reported by the non-Vantec
adapters is just under 1/8th of the drive capacity, which would be
consistent with MBR reporting the partition size in logical sectors
(counting 4K sectors instead of 512 byte sectors).

Assuming I'm right, this is either a jumper setting or fixed feature of
the particular drive you are using. If it is a jumper setting (for 4K
native vs 512-byte emulation) and you want to change to the 512 byte
emulation mode, you would need to competely erase the drive after
changing the jumper, because all content of the drive is set up assuming
4K sectors.

System Information didn't report the sector size, but I've found how to
get it from the diskutil command. With your drive connected to the
Vantec adapter, use the following commands in Terminal:

diskutil list

Confirm that the drive is identified as /dev/disk2 (as it was in your
System Information report). If it has been assigned to a different disk
number, adjust the following command accordingly.

diskutil info disk2 | grep Block

I will just give all of "diskutil info disk2" for all details (4096 bytes for its block size):
$ diskutil info disk2
Device Identifier: disk2
Device Node: /dev/disk2
Part of Whole: disk2
Device / Media Name: WDC WD20 EZRX-00D8PB0 Media
Volume Name: Not applicable (no file system)
Mounted: Not applicable (no file system)
File System: None
Content (IOContent): GUID_partition_scheme
OS Can Be Installed: No
Media Type: Generic
Protocol: USB
SMART Status: Not Supported
Total Size: 2.0 TB (2000398934016 Bytes) (exactly 3907029168 512-Byte-Units)
Volume Free Space: Not applicable (no file system)
Device Block Size: 4096 Bytes
Read-Only Media: No
Read-Only Volume: Not applicable (no file system)
Ejectable: Yes
Whole: Yes
Internal: No
OS 9 Drivers: No
Low Level Format: Not supporte


Try it again with one of the non-Vantec adapters.

Both said 512 bytes:

#1:
$ diskutil info disk2
Device Identifier: disk2
Device Node: /dev/disk2
Part of Whole: disk2
Device / Media Name: WDC WD20 EZRX-00D8PB0 Media
Volume Name: Not applicable (no file system)
Mounted: Not applicable (no file system)
File System: None
Content (IOContent): FDisk_partition_scheme
OS Can Be Installed: No
Media Type: Generic
Protocol: USB
SMART Status: Not Supported
Total Size: 2.0 TB (2000398934016 Bytes) (exactly 3907029168 512-Byte-Units)
Volume Free Space: Not applicable (no file system)
Device Block Size: 512 Bytes
Read-Only Media: No
Read-Only Volume: Not applicable (no file system)
Ejectable: Yes
Whole: Yes
Internal: No
OS 9 Drivers: No
Low Level Format: Not supported

#2:
$ diskutil info disk2
Device Identifier: disk2
Device Node: /dev/disk2
Part of Whole: disk2
Device / Media Name: WDC WD20 EZRX-00D8PB0 Media
Volume Name: Not applicable (no file system)
Mounted: Not applicable (no file system)
File System: None
Content (IOContent): FDisk_partition_scheme
OS Can Be Installed: No
Media Type: Generic
Protocol: USB
SMART Status: Not Supported
Total Size: 2.0 TB (2000398934016 Bytes) (exactly 3907029168 512-Byte-Units)
Volume Free Space: Not applicable (no file system)
Device Block Size: 512 Bytes
Read-Only Media: No
Read-Only Volume: Not applicable (no file system)
Ejectable: Yes
Whole: Yes
Internal: No
OS 9 Drivers: No
Low Level Format: Not supported


I expect you will see 4096 bytes from the Vantec, but 512 bytes from the
non-Vantec.

Yep, you were correct.


Hmm, I never changed anything on this drive. FYI,
http://imgur.com/a/49Agm for the 2 shots of the drive (label and
connectors). Bah, I have to erase it to do that if supported?

That shows it is a Western Digital Green, model WD20EZRX. According to
WD's web site, that drive uses Advanced Format (AF), i.e. it has 4K
sectors. The label doesn't mention jumpers, so it probably doesn't have
one to change how 4K sectors are handled. (Older WD drives did have a
jumper relating to AF, but it only affected performance with Windows XP.
That issue can be addressed in software with more recent WD drives.)


Input or corrections from others with more experience in this area is
welcome. Here's my interpretation of the situation.

I don't have enough detailed technical knowledge of how 4K sector size
is implemented at the level of the ATA command set, but from what I have
read it is clearly backward compatible with older OSes (e.g. Windows
XP), only affecting performance, which implies that for an internal
drive, the 512 byte emulation mode is used automatically when the OS
doesn't support native 4K sectors. It is therefore a choice made by the
OS whether to use 4K sectors (if the drive supports them).

For an external drive, the USB to SATA bridge is either an older bridge
which only supports 512 byte sectors (in which case it would use 512e
mode with an Advanced Format drive), or a newer bridge which can support
either 512 byte or 4K sectors. If the bridge supports 4K sectors, it may
make an executive decision about whether to use 512e or 4K mode with an
Advanced Format drive.

For Windows XP compatibility, the sectors must be 512 bytes. The maximum
drive capacity supported by Windows XP is 2 TB (due to Master Boot
Record limitations), therefore any 2 TB or smaller external drive SHOULD
use 512 byte sectors, just in case it is plugged into Windows XP. That
suggests it is reasonble for a USB to SATA bridge to force 512e mode
with a 2 TB or smaller drive, even if the bridge supports 4K sectors.

If the drive capacity is greater than 2 TB then it cannot be used (to
its full capacity) with Windows XP anyway, so a USB to SATA bridge which
supports 4K sectors can use them if the drive also supports them.

Your drive happens to be exactly 2 TB, so it might be a victim of
different choices made by your USB to SATA bridges.

I expect that your Vantec adapter is able to pass through the commands
and information required to allow the host to use 4K sectors, and is not
forcing 512e mode for 2 TB and smaller drives. The Mac has supported 4K
sectors since Mac OS X 10.4 (Tiger), so it set up the drive's partition
table using 4K sectors.

Your other two adapters are accessing the drive in 512e mode, which is
not compatible with how the drive is formatted. I don't have enough
information to determine whether this is a choice the adapters made
because the drive capacity is 2 TB or smaller, or if they simply don't
support 4K sectors.

Because the drive has been formatted as 4K, the partition table doesn't
make sense when the drive is accessed via your non-Vantec adapters.

So Mac OS X partitioned and formatted this new drive with 4K with Vantec
adapter.


I wonder what happened if I used the non-Vantec adapters and redid the
partitions. Would Vantec have problems then?

Not clear to me yet.

In that case the drive would be set up using 512 byte (emulated)
sectors, but I can't see anything in the MBR (or GPT) which specifies
the sector size. The host can probably deduce the sector size from the
partition table given the drive capacity, in which case it may still
work with your Vantec adapter.

If the host relies on the sector size reported by the drive via the USB
to SATA bridge, there would be a mutual incompatiblity between your
adapters for Advanced Format drives (or at least AF drives of 2 TB or
smaller).

Sheesh, I didn't think this would be complex and difficult.

It isn't for internal drives (unless moved to an older OS which doesn't
support the sector size), nor for preassembled external drives (which
come with a manufacturer-supplied bridge board set up correctly for the
drive).

Well, I would still want to be able to use it with older OSes and
machines too.


If you are using external drives with a mixture of bridges, you can run
into this sort of problem due to different implementations in the
bridges.


--
Quote of the Week: "Yo mama's glasses are so thick, she can burn ants with them." --unknown
Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly.
/\___/\ Ant(Dude) @ http://antfarm.home.dhs.org (Personal Web Site)
/ /\ /\ \ Ant's Quality Foraged Links: http://aqfl.net
| |o o| |
\ _ / Please nuke ANT if replying by e-mail privately. If credit-
( ) ing, then please kindly use Ant nickname and AQFL URL/link.

Hi again.

I decided to do more experiments for curiousity and fun. I decided to
use one of the non-Vantec brands and redo the 3 partitions (2 Mac OS
Extended FS + 1 FAT) on the drive. I didn't put any data on it yet. I
disconnected and connected with the Vantec brand, and it couldn't see
them! I put in the OTHER non-Vantec brand, and it saw them! So both
non-Vantec brands could see it, but not Vantec. I reconnected them to
the 64-bit W7 EE SP1 laptop/notebook. Similiar results even though it
told me that FAT partition (E was unreadable and asked me to format it
or not. Oy!! FYI from Mac OS X v10.10.5 (Yosemite):

$ diskutil info disk2
Device Identifier: disk2
Device Node: /dev/disk2
Part of Whole: disk2
Device / Media Name: WDC WD20 EZRX-00D8PB0 Media
Volume Name: Not applicable (no file system)
Mounted: Not applicable (no file system)
File System: None

Content (IOContent): GUID_partition_scheme
OS Can Be Installed: No
Media Type: Generic
Protocol: USB
SMART Status: Not Supported

Total Size: 2.0 TB (2000398934016 Bytes) (exactly 3907029168 512-Byte-Units)
Volume Free Space: Not applicable (no file system)
Device Block Size: 512 Bytes

Read-Only Media: No
Read-Only Volume: Not applicable (no file system)
Ejectable: Yes

Whole: Yes
Internal: No
OS 9 Drivers: No
Low Level Format: Not supported


Is there even a way to make all three and others, that I don't have,
work? Maybe I need a different brand? I might as well get this issue
resolved to avoid later. Darn electronics like computers.
--
Quote of the Week: "Yo mama's glasses are so thick, she can burn ants with them." --unknown
Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly.
/\___/\ Ant(Dude) @ http://antfarm.home.dhs.org (Personal Web Site)
/ /\ /\ \ Ant's Quality Foraged Links: http://aqfl.net
| |o o| |
\ _ / Please nuke ANT if replying by e-mail privately. If credit-
( ) ing, then please kindly use Ant nickname and AQFL URL/link.

....
You have partitioned the disk(s) on a Mac. This means the GUID is used
as standard file system. If a Windows computer should be able to see and
use the disk(s), you must use the MBR (Master Boot record) when you
partition the disk(s).

But Mac couldn't read it too when I switched to the other USB adapter
(no brand vs. Vantec brand).


In DiskUtility select 'Partition', choose the number of partitions,
select 'Preferences' and choose 'Master Boot Record', click OK, select
'HFS+ (Journalized', click 'Apply'.

Now the disk will be with three HFS+ partitions. Go to the sidebar and
mark the one you need for FAT32 and then select 'Erase' in the upper
tabs. select 'FAT32' in the popup menu, click 'Erase'. The selected
FAT32 partition will now be fully win compatible.

That did not help. Changing between the non-Vantec and Vantec cable
adapters resulted unable to read drive errors again.


BUT - the two HFS+ partitions may not be visible in Win7. If I recall
right it isn't all the Win7 versions that are able to see and read/write
to/from HFS+ partitions.

That's OK since I only wanted one FAT partition for both platforms. The
other two partitions would be for encrypted Time Machine backups and
other Mac files for Macs only.
--
Quote of the Week: "Yo mama's glasses are so thick, she can burn ants with them." --unknown
Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly.
/\___/\ Ant(Dude) @ http://antfarm.home.dhs.org (Personal Web Site)
/ /\ /\ \ Ant's Quality Foraged Links: http://aqfl.net
| |o o| |
\ _ / Please nuke ANT if replying by e-mail privately. If credit-
( ) ing, then please kindly use Ant nickname and AQFL URL/link.

Ant wrote:

I decided to do more experiments for curiousity and fun. I decided to
use one of the non-Vantec brands and redo the 3 partitions (2 Mac OS
Extended FS + 1 FAT) on the drive. I didn't put any data on it yet. I
disconnected and connected with the Vantec brand, and it couldn't see
them! I put in the OTHER non-Vantec brand, and it saw them! So both
non-Vantec brands could see it, but not Vantec.

That suggests the host relies on the sector size reported by the USB to
SATA bridge, and is not trying to deduce the sector size from the
partition map.

I reconnected them to the 64-bit W7 EE SP1 laptop/notebook. Similiar
results even though it told me that FAT partition (E was unreadable and
asked me to format it or not. Oy!!

That probably means OS X isn't doing anything unusual.

Is there even a way to make all three and others, that I don't have,
work? Maybe I need a different brand? I might as well get this issue
resolved to avoid later. Darn electronics like computers.

For more data, try other drives with different capacities.

I expect that you will run into the same problem with any Advanced
Format drive: the Vantec adapter will always use 4K sectors, the other
adapters will always use 512e mode (because they don't support 4K
sectors).

If you use a drive which doesn't support Advanced Format, I expect all
three adapters will be compatible, because they will all be using 512
byte sectors (since that is what the drive uses).

--
David Empson

I decided to do more experiments for curiousity and fun. I decided to
use one of the non-Vantec brands and redo the 3 partitions (2 Mac OS
Extended FS + 1 FAT) on the drive. I didn't put any data on it yet. I
disconnected and connected with the Vantec brand, and it couldn't see
them! I put in the OTHER non-Vantec brand, and it saw them! So both
non-Vantec brands could see it, but not Vantec.

That suggests the host relies on the sector size reported by the USB to
SATA bridge, and is not trying to deduce the sector size from the
partition map.

I reconnected them to the 64-bit W7 EE SP1 laptop/notebook. Similiar
results even though it told me that FAT partition (E was unreadable and
asked me to format it or not. Oy!!

That probably means OS X isn't doing anything unusual.

Is there even a way to make all three and others, that I don't have,
work? Maybe I need a different brand? I might as well get this issue
resolved to avoid later. Darn electronics like computers.

For more data, try other drives with different capacities.

Yeah, when I get more drives. It sounds like this would only happen with
the newer big drives since they can use 4K sizes?


I expect that you will run into the same problem with any Advanced
Format drive: the Vantec adapter will always use 4K sectors, the other
adapters will always use 512e mode (because they don't support 4K
sectors).

And we can't change the sector sizes in Disk Utility? I didn't see those
options. :/
--
Quote of the Week: "Yo mama's glasses are so thick, she can burn ants with them." --unknown
Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly.
/\___/\ Ant(Dude) @ http://antfarm.home.dhs.org (Personal Web Site)
/ /\ /\ \ Ant's Quality Foraged Links: http://aqfl.net
| |o o| |
\ _ / Please nuke ANT if replying by e-mail privately. If credit-
( ) ing, then please kindly use Ant nickname and AQFL URL/link.

Ant wrote:

I decided to do more experiments for curiousity and fun. I decided to
use one of the non-Vantec brands and redo the 3 partitions (2 Mac OS
Extended FS + 1 FAT) on the drive. I didn't put any data on it yet. I
disconnected and connected with the Vantec brand, and it couldn't see
them! I put in the OTHER non-Vantec brand, and it saw them! So both
non-Vantec brands could see it, but not Vantec.

That suggests the host relies on the sector size reported by the USB to
SATA bridge, and is not trying to deduce the sector size from the
partition map.

I reconnected them to the 64-bit W7 EE SP1 laptop/notebook. Similiar
results even though it told me that FAT partition (E was unreadable and
asked me to format it or not. Oy!!

That probably means OS X isn't doing anything unusual.

Is there even a way to make all three and others, that I don't have,
work? Maybe I need a different brand? I might as well get this issue
resolved to avoid later. Darn electronics like computers.

For more data, try other drives with different capacities.

Yeah, when I get more drives. It sounds like this would only happen with
the newer big drives since they can use 4K sizes?

It is specific to "Advanced Format" (4K sector) drives, which are newer
ones, but they exist in capacities smaller than 2 TB (judging from the
list of models at Western Digital).

What I don't know is whether your adapters change behaviour depending on
drive capacity. It seems most likely adapter is changing behaviour
depending on drive capacity. For your current WD 2 GB drive it is
passing through the 4K sector size. It might behave differently with
smaller capacity drives that use 4K sectors.

I'm assuming your other adapters simply don't support 4K sectors, but it
is also possible they change behaviour for drive capacities over 2 TB,
because drives over 2 TB are effectively unusable by Windows XP (or
earlier), so there is little need to force 512 byte sectors with drives
over 2 TB.

I expect that you will run into the same problem with any Advanced
Format drive: the Vantec adapter will always use 4K sectors, the other
adapters will always use 512e mode (because they don't support 4K
sectors).

And we can't change the sector sizes in Disk Utility? I didn't see those
options. :/

The sector size is an integral feature of the drive mechanism: either
512 bytes or 4096 bytes per sector. Drives with 4K sectors ("Advanced
Format") support a backward compatibility mode ("512e") which allows
them to work with older OS versions which only understand 512 byte
sectors, but with a newer OS the native 4K sector size is used.

Adding a USB to SATA bridge into the path introduces an additional
variable: whether the bridge/adapter supports 4K sectors. If it doesn't,
the host is forced to use 512 byte sectors and is unable to detect that
the drive is really using 4K sectors.

In theory, an OS new enough to support 4K sectors could opt to use 512
byte emulation mode even if the drive has 4K sectors, but I haven't
spotted a way to force that in OS X. This would have performance
disadvantages.

--
David Empson

Interesting and thanks. I looked at Vantec's web site and saw this
http://www.vantecusa.com/en/faq/index 's FAQ #13:

"Will the CB-ISATAU2 work with Advanced Format (4Ksector) Drives?
No, it will not work with Advanced Format (4K sector) Drives. We do have
other product that will like CB-ISA200-U3 or CB-ISATAU3."

Huh? How come I was able to format it and use it? Obviously, it didn't
work with the other adapters after that. :/

I wonder if this problem will still occur if connected to desktops'
motherboards inside computers.

....
It is specific to "Advanced Format" (4K sector) drives, which are newer
ones, but they exist in capacities smaller than 2 TB (judging from the
list of models at Western Digital).

What I don't know is whether your adapters change behaviour depending on
drive capacity. It seems most likely adapter is changing behaviour
depending on drive capacity. For your current WD 2 GB drive it is
passing through the 4K sector size. It might behave differently with
smaller capacity drives that use 4K sectors.

I'm assuming your other adapters simply don't support 4K sectors, but it
is also possible they change behaviour for drive capacities over 2 TB,
because drives over 2 TB are effectively unusable by Windows XP (or
earlier), so there is little need to force 512 byte sectors with drives
over 2 TB.
....
The sector size is an integral feature of the drive mechanism: either
512 bytes or 4096 bytes per sector. Drives with 4K sectors ("Advanced
Format") support a backward compatibility mode ("512e") which allows
them to work with older OS versions which only understand 512 byte
sectors, but with a newer OS the native 4K sector size is used.

Adding a USB to SATA bridge into the path introduces an additional
variable: whether the bridge/adapter supports 4K sectors. If it doesn't,
the host is forced to use 512 byte sectors and is unable to detect that
the drive is really using 4K sectors.

In theory, an OS new enough to support 4K sectors could opt to use 512
byte emulation mode even if the drive has 4K sectors, but I haven't
spotted a way to force that in OS X. This would have performance
disadvantages.
....
--
Quote of the Week: "Yo mama's glasses are so thick, she can burn ants with them." --unknown
Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly.
/\___/\ Ant(Dude) @ http://antfarm.home.dhs.org (Personal Web Site)
/ /\ /\ \ Ant's Quality Foraged Links: http://aqfl.net
| |o o| |
\ _ / Please nuke ANT if replying by e-mail privately. If credit-
( ) ing, then please kindly use Ant nickname and AQFL URL/link.

In message
Ant wrote:
I decided to do more experiments for curiousity and fun. I decided to
use one of the non-Vantec brands and redo the 3 partitions (2 Mac OS
Extended FS + 1 FAT) on the drive. I didn't put any data on it yet. I
disconnected and connected with the Vantec brand, and it couldn't see
them! I put in the OTHER non-Vantec brand, and it saw them! So both
non-Vantec brands could see it, but not Vantec.

That suggests the host relies on the sector size reported by the USB to
SATA bridge, and is not trying to deduce the sector size from the
partition map.

I reconnected them to the 64-bit W7 EE SP1 laptop/notebook. Similiar
results even though it told me that FAT partition (E was unreadable and
asked me to format it or not. Oy!!

That probably means OS X isn't doing anything unusual.

Is there even a way to make all three and others, that I don't have,
work? Maybe I need a different brand? I might as well get this issue
resolved to avoid later. Darn electronics like computers.

For more data, try other drives with different capacities.

Yeah, when I get more drives. It sounds like this would only happen with
the newer big drives since they can use 4K sizes?

Newer, not necessarily big. Pretty much any drive in the last X years,
where X is a number I don't know but is probably 3-5 depending on
manufacturer.

That is to say, you can buy a brand new 1TB drive with 4K blocks. Both
Seagate and WD have been shipping 4K drives since 2010, though it's not
clear to me on 5 seconds with google when (or if) they moved all drives
to 4K.

And we can't change the sector sizes in Disk Utility? I didn't see those
options. :/

You cannot change the physical characteristics of the drive.

--
and I swear it happened just like this: / a sigh, a cry, a hungry kiss,
the Gates of Love they budged an inch / I can't say much has happened
since / but CLOSING TIME

Newer, not necessarily big. Pretty much any drive in the last X years,
where X is a number I don't know but is probably 3-5 depending on
manufacturer.

That is to say, you can buy a brand new 1TB drive with 4K blocks. Both
Seagate and WD have been shipping 4K drives since 2010, though it's not
clear to me on 5 seconds with google when (or if) they moved all drives
to 4K.

And we can't change the sector sizes in Disk Utility? I didn't see those
options. :/

You cannot change the physical characteristics of the drive.

Interesting. This is all news to me! Thanks.
--
Quote of the Week: "Yo mama's glasses are so thick, she can burn ants with them." --unknown
Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly.
/\___/\ Ant(Dude) @ http://antfarm.home.dhs.org (Personal Web Site)
/ /\ /\ \ Ant's Quality Foraged Links: http://aqfl.net
| |o o| |
\ _ / Please nuke ANT if replying by e-mail privately. If credit-
( ) ing, then please kindly use Ant nickname and AQFL URL/link.

On 11/21/2015 11:05 PM, Lewis wrote:
In message
Ant wrote:

Yeah, when I get more drives. It sounds like this would only happen with
the newer big drives since they can use 4K sizes?

Newer, not necessarily big. Pretty much any drive in the last X years,
where X is a number I don't know but is probably 3-5 depending on
manufacturer.

That is to say, you can buy a brand new 1TB drive with 4K blocks. Both
Seagate and WD have been shipping 4K drives since 2010, though it's not
clear to me on 5 seconds with google when (or if) they moved all drives
to 4K.

You need to be clear whether you are talking about _physical_
sector size or _logical_ sector size. What are common today are
drives that are "4K physical / 512B logical", i.e. drives with
4096-byte physical sectors addressed in 512-byte blocks. To the
OS, they work much like the older 512B/512B drives, but with the
caveat that there is a huge performance penalty for writes that
are not multiples of 4K bytes aligned on 4K boundaries. The
drives will handle it, but the read/modify/write to insert data
into just a portion of a 4K-byte sector takes time.

What you are starting to see now are drives that are "4K physical /
4K logical" and can only be accessed in 4096-byte blocks. Not all
operating systems can handle those. An interesting side effect
that surprises some people is that MBR partitioning can be used
for these drives up to 16TB, the limit being 2^32 logical sectors.

--
Bob Nichols AT comcast.net I am "RNichols42"