Alternative terms for master and slave

On 2020-12-20, Dimiter_Popoff <dp@tgi-sci.com> wrote:

> SATA does just a single device per link so no "master/slave" to
> be talked about

Odd. All my SATA cables have _two_ ends, and there's a device at each
end. I was under the distinct impression that at one end is the master
and at the other end there's a slave.

There are are tons of other point-point protocols that use the
master/slave nomenclature, even if SATA doesn't.

--
Grant

On 12/20/2020 20:17, Grant Edwards wrote:
> On 2020-12-20, Dimiter_Popoff <dp@tgi-sci.com> wrote:
> 
>> SATA does just a single device per link so no "master/slave" to
>> be talked about
> 
> Odd. All my SATA cables have _two_ ends, and there's a device at each
> end. I was under the distinct impression that at one end is the master
> and at the other end there's a slave.
> 
> There are are tons of other point-point protocols that use the
> master/slave nomenclature, even if SATA doesn't.
> 
> --
> Grant
> 

Hah, you may call them that of course, some people may even be
calling them that.

But for people familiar with ATA and subsequently SATA and in the
context above "master" and "slave" refer to device 0 and device 1
on the ATA cable, you probably remember your parallel ATA (aka IDE)
cables having 3 connectors: one for the host, one for device 0
(which some called "master") and one for device 1 (which some
called "slave"). Actually I don't know where that master/slave
came from, perhaps from the times ATA was called IDE which was before
I used any ATA drives in our products (used SCSI back then, until
they stopped at 810MB or so for 2.5" drives).

Dimiter

======================================================
Dimiter Popoff, TGI             http://www.tgi-sci.com
======================================================
http://www.flickr.com/photos/didi_tgi/

Am 20.12.2020 um 22:23 schrieb Dimiter_Popoff:

> But for people familiar with ATA and subsequently SATA and in the
> context above "master" and "slave" refer to device 0 and device 1
> on the ATA cable, 

Not really.  Parallel ATA learnd this ("cable select") as an option long 
after the master/slave roles had been assigned.

The primary choice was made by jumpers on the devices, with three 
options: master, slave, or cable-select.  Only if both devices were 
jumpered CS would their position on the cable have any significance.

The master/slave terminology was attached because device 1 was unable to 
work on its own.  I.e. a single device would always have to be device 0.

On 12/21/2020 0:56, Hans-Bernhard Bröker wrote:
> Am 20.12.2020 um 22:23 schrieb Dimiter_Popoff:
> 
>> But for people familiar with ATA and subsequently SATA and in the
>> context above "master" and "slave" refer to device 0 and device 1
>> on the ATA cable, 
> 
> Not really.  Parallel ATA learnd this ("cable select") as an option long 
> after the master/slave roles had been assigned.
> 
> The primary choice was made by jumpers on the devices, with three 
> options: master, slave, or cable-select.  Only if both devices were 
> jumpered CS would their position on the cable have any significance.
> 
> The master/slave terminology was attached because device 1 was unable to 
> work on its own.  I.e. a single device would always have to be device 0.
> 

Not so. Clearly you have never designed in ATA drives.

The "cable select" signal is just a pin connected to the host and to
one of the two devices, thus enabling them to know which of the two is
device 0 and which is device 1 (lookup d1153r18, it is explained well
enough there).
The jumpers on the devices are to override the cable select connection
and are unnecessary on correctly designed hosts/devices.

And of course you can have a single device on an ATA cable which
is device 1, although it is rarely done and typically unnecessary.

Dimiter


======================================================
Dimiter Popoff, TGI             http://www.tgi-sci.com
======================================================
http://www.flickr.com/photos/didi_tgi/

Am 21.12.2020 um 16:29 schrieb Dimiter_Popoff:

> Not so. Clearly you have never designed in ATA drives.

The level of your arrogance never disappoints.

On 12/22/2020 0:44, Hans-Bernhard Bröker wrote:
> Am 21.12.2020 um 16:29 schrieb Dimiter_Popoff:
> 
>> Not so. Clearly you have never designed in ATA drives.
> 
> The level of your arrogance never disappoints.

Sorry, did not mean to be arrogant. I can see it can be interpreted
like this though, I must have been thinking on all the history I have
had with ATA drives, CPLD interfaces and drivers I have been doing for
them. Not very interesting or complex to do but quite bulky.
Sorry again if I offended you.

Dimiter