Why do SATA drives have those tiny pin power plugs

It seems that since the beginning of computers, everything had Molex
plugs and they worked fine. To use a SATA drive, I need an adaptor to
convert to those tiny pins on the drive. I almost wonder how enough
current can get thru those tiny pins.

What gets me most, is why all those pins are needed. The molex is
supplying +5v and +12v with two ground wires. Obviously the same
voltages are going to the drive, via a much more complex cable plug and
in a much more fragile means.

I understand the data cables differ greatly on a SATA drive, versus the
older IDE types, but the need to change the power plug makes no sense at
all. If they need to provide those two voltages to multiple parts of the
drive, I'd think they could have done that onboard, on the drive itself,
and not required a special adaptor to convert from the 4 pin Molex to
this thing (whatever it's called).

On Thu, 19 Oct 2017 03:31:11 -0500, wrote:

What gets me most, is why all those pins are needed. The molex is
supplying +5v and +12v with two ground wires. Obviously the same
voltages are going to the drive, via a much more complex cable plug and
in a much more fragile means.

They have more pins because they are small and each pin can carry less
current (3 pins for each cable). The connector supplies 3.3v as well as
12v and 5v.

Have a google for sata power pins.

--
Faster, cheaper, quieter than HS2
and built in 5 years;
UKUltraspeed http://www.500kmh.com/

wrote:
It seems that since the beginning of computers, everything had Molex
plugs and they worked fine. To use a SATA drive, I need an adaptor to
convert to those tiny pins on the drive. I almost wonder how enough
current can get thru those tiny pins.

What gets me most, is why all those pins are needed. The molex is
supplying +5v and +12v with two ground wires. Obviously the same
voltages are going to the drive, via a much more complex cable plug and
in a much more fragile means.

I understand the data cables differ greatly on a SATA drive, versus the
older IDE types, but the need to change the power plug makes no sense at
all. If they need to provide those two voltages to multiple parts of the
drive, I'd think they could have done that onboard, on the drive itself,
and not required a special adaptor to convert from the 4 pin Molex to
this thing (whatever it's called).


The SATA drives were designed for server backplanes. Servers allow
"Hot Plug", and IT staff are installing and removing hard drives
all day long from the front of the server, while the server
remains powered. That's why they have server backplanes and
hot plug drive bays.

The ThermalTake dock kind of product, uses the backplane connector
idea too (drive slides into dock, like the dock was a toaster).
Docks can exist today, because of the SATA being designed for
server usage.

The SATA drive interface, is modeled after this pre-existing scheme.
But this connector has way too many contacts for SATA usage. SATA
data is a serial bus, whereas this generation of connector used
wide parallel buses instead. In typical usage, the SCA drives
used a sled with a lever, which did a very nice job of
sliding them into place.

https://en.wikipedia.org/wiki/Single...tor_Attachment

The SATA connector was designed for servers first, and whatever
happened on desktops, hardly mattered.

The power section uses the same contact scheme as the data section,
so that the insertion force and capture requirements will be
similar. The L-shape in the plastic, helps guide it too
and prevent flipped insertion.

When used to carry power, the SATA contacts are rated at 1 ampere each.
3,3V,5V,12V,GND,GND times three pads each, gives 3 amps
on each of those groups. My guess is, the connector
is not designed to provide "max power" on the first three
items, all at the same time. A 3.5" drive uses 5V,12V.
A 2.5" drive (which uses the same connector) uses 5V.
There were a few SSDs that used 3.3V only (but they
also used the microSATA connector, so don't count).
But generally, the 3.3V is hardly used. And a lot of
"adapter cables" don't even have 3.3V connected, so
your 3.3V SSD wouldn't work anyway. Whereas a SATA power
coming straight from the PSU, has all the rails wired up.

*******

The Molex is great for hand wiring.

It has a high current rating.

But it's not suitable for backplane usage. And the SATAIO
organization had "server on the brain" when they did the
SATA spec.

Paul

On Thu, 19 Oct 2017 11:45:37 -0400, Paul wrote:

wrote:
It seems that since the beginning of computers, everything had Molex
plugs and they worked fine. To use a SATA drive, I need an adaptor to
convert to those tiny pins on the drive. I almost wonder how enough
current can get thru those tiny pins.

What gets me most, is why all those pins are needed. The molex is
supplying +5v and +12v with two ground wires. Obviously the same
voltages are going to the drive, via a much more complex cable plug and
in a much more fragile means.

I understand the data cables differ greatly on a SATA drive, versus the
older IDE types, but the need to change the power plug makes no sense at
all. If they need to provide those two voltages to multiple parts of the
drive, I'd think they could have done that onboard, on the drive itself,
and not required a special adaptor to convert from the 4 pin Molex to
this thing (whatever it's called).


The SATA drives were designed for server backplanes. Servers allow
"Hot Plug", and IT staff are installing and removing hard drives
all day long from the front of the server, while the server
remains powered. That's why they have server backplanes and
hot plug drive bays.

The ThermalTake dock kind of product, uses the backplane connector
idea too (drive slides into dock, like the dock was a toaster).
Docks can exist today, because of the SATA being designed for
server usage.

The SATA drive interface, is modeled after this pre-existing scheme.
But this connector has way too many contacts for SATA usage. SATA
data is a serial bus, whereas this generation of connector used
wide parallel buses instead. In typical usage, the SCA drives
used a sled with a lever, which did a very nice job of
sliding them into place.

https://en.wikipedia.org/wiki/Single...tor_Attachment

The SATA connector was designed for servers first, and whatever
happened on desktops, hardly mattered.

The power section uses the same contact scheme as the data section,
so that the insertion force and capture requirements will be
similar. The L-shape in the plastic, helps guide it too
and prevent flipped insertion.

When used to carry power, the SATA contacts are rated at 1 ampere each.
3,3V,5V,12V,GND,GND times three pads each, gives 3 amps
on each of those groups. My guess is, the connector
is not designed to provide "max power" on the first three
items, all at the same time. A 3.5" drive uses 5V,12V.
A 2.5" drive (which uses the same connector) uses 5V.
There were a few SSDs that used 3.3V only (but they
also used the microSATA connector, so don't count).
But generally, the 3.3V is hardly used. And a lot of
"adapter cables" don't even have 3.3V connected, so
your 3.3V SSD wouldn't work anyway. Whereas a SATA power
coming straight from the PSU, has all the rails wired up.

*******

The Molex is great for hand wiring.

It has a high current rating.

But it's not suitable for backplane usage. And the SATAIO
organization had "server on the brain" when they did the
SATA spec.

Paul

Interesting. I know it's not getting 3.3 volts because it's power comes
from an adaptor on a Molex plug.

What you are saying about it being made to slide into a rail, makes
sense. I can see that being easy to do. Plugging/unplugging a HDD with
the power LIVE seems risky at the least though. I would not even
consider doing that.

I will say that I do like the data cable setup on the SATA drives. No
jumpers is a big plus, and those cables are a lot easier to plug in. But
if you ask me, the power plugs are harder to get into the slot,
especially inside a dark tower case.

I was sort of wondering about those slide in drive bays. That would make
life easier on me, and I would not have to leave my tower case open all
the time, because I regularly swap drives. What I have is a large drive
with XP on it. But recently I decided to install PC Linux OS (2009
version for 32 bit). I am not a real linux user, in fact most linux
distros wont work or I just cant understand them. But I kind of like
this old one, and it's handy for certain things.

I was not willing to let Linux wreck my XP setup (dual booting), even
though it's supposed to work. Having XP on one drive and Linux on the
other is much preferred. I just have to keep changing the drives all the
time. What i have now, is that both drives have a power cable on them,
so I only have to change the data cable. But a plug in rail would be
nice, and I could close the case for once.

On Thu, 19 Oct 2017 15:18:08 -0500, wrote:

What you are saying about it being made to slide into a rail, makes
sense. I can see that being easy to do. Plugging/unplugging a HDD with
the power LIVE seems risky at the least though. I would not even
consider doing that.

I will say that I do like the data cable setup on the SATA drives. No
jumpers is a big plus, and those cables are a lot easier to plug in. But
if you ask me, the power plugs are harder to get into the slot,
especially inside a dark tower case.

I was sort of wondering about those slide in drive bays. That would make
life easier on me, and I would not have to leave my tower case open all
the time, because I regularly swap drives. What I have is a large drive
with XP on it. But recently I decided to install PC Linux OS (2009
version for 32 bit). I am not a real linux user, in fact most linux
distros wont work or I just cant understand them. But I kind of like
this old one, and it's handy for certain things.

I use an Icy-dock device. It fits directly into one of the large
openings for an optical drive, and has a slot so you simply insert a
SATA drive and the connections are made without any cable juggling. It
makes swapping drives simple. I use a third party program called
HotSwap (http://mt-naka.com/hotswap/index_enu.htm) just to ensure the
drive being removed is OK to pull.

On Thu, 19 Oct 2017 16:28:51 -0500, Charlie Hoffpauir
wrote:

On Thu, 19 Oct 2017 15:18:08 -0500, wrote:

What you are saying about it being made to slide into a rail, makes
sense. I can see that being easy to do. Plugging/unplugging a HDD with
the power LIVE seems risky at the least though. I would not even
consider doing that.

I will say that I do like the data cable setup on the SATA drives. No
jumpers is a big plus, and those cables are a lot easier to plug in. But
if you ask me, the power plugs are harder to get into the slot,
especially inside a dark tower case.

I was sort of wondering about those slide in drive bays. That would make
life easier on me, and I would not have to leave my tower case open all
the time, because I regularly swap drives. What I have is a large drive
with XP on it. But recently I decided to install PC Linux OS (2009
version for 32 bit). I am not a real linux user, in fact most linux
distros wont work or I just cant understand them. But I kind of like
this old one, and it's handy for certain things.

I use an Icy-dock device. It fits directly into one of the large
openings for an optical drive, and has a slot so you simply insert a
SATA drive and the connections are made without any cable juggling. It
makes swapping drives simple. I use a third party program called
HotSwap (http://mt-naka.com/hotswap/index_enu.htm) just to ensure the
drive being removed is OK to pull.

I assume Icy Dock is the product name. That sounds like what I want. I
wont need to hot swap though. Both drives contain an operating system so
I'll have to shutdown and reboot anyhow.

Thanks