Rick's b.log - entry 2023/11/23

Inside a USB DVD player

Well, by the magic of just happening to have one on the table here along with a very conveniently placed screwdriver, we can take a peek inside.

A portable USB DVD player.

This device is an LG "Portable Super Multi Drive". It reads and writes CDs, DVDs, and DVD-RWs...at "Ultra speed".
It was made on March 25^th 2010.

The -RW part is important, as normal DVD writing literally burns into the layer that the DVD reader reads, but since the RW format is reusable, it uses the heat of the laser to cause a dye change which is perceived as the same thing. The problem here is that the difference between the burned and non-burned parts (that provide the low level stream of data) is actually rather slight. Less than traditional DVD readers are capable of distinguishing.

Anyway, flip it over, six screws. We can see it is ROM VER. : 1.01 as if this means anything to the average consumer.

Once the screws have been removed, flip it back the right way up and the lid comes away easily.

A portable USB DVD player with its cover removed.

What we can see inside is... a Model GT10N DVD drive with something sticking out of the back, buried under a load of radio shielding. Let's remove that, too.

An interface board.

That, on the right there, that's a SATA interface. So what's actually inside this external DVD writer is basically a generic writer with a SATA interface that would have been found in laptops and such. Here it is stuck into a plastic box with a USB interface hanging out the back.
Note that there appears to be provision (not fitted) for some sort of audio socket on the left.

Let's go a little closer on the interface.

The interface board.

The heart of the interface is an initio INIC-1610 USB to SATA interface. It has an integrated Turbo 8051 processor and 16KB SRAM, and it supports Mass Storage Class Bulk-Only function. It can handle 60MB/sec incoming to a 1.5G SATA interface.

The datasheet implies that the input should be a 12MHz clock, but I see a 25MHz crystal. Perhaps it's ÷2 or something?

To the left of that is an MX25L512 which is a CMOS serial EEPROM with 64K capacity. When the INIC-1610 powers up, it will automatically read 4K from an SPI Flash (this chip) which contains the firmware; along with the option to copy a further 12K of program code from the SPI flash if necessary.

On the far left is a 7217A-33 which converts the USB 5Vish into 3.3V.

Okay, now let's pop open the lid of the DVD unit itself.

The DVD controller board.

Hmmm, that's not terribly interesting.

Maybe underneath?

The DVD controller board, other side.

Well, here's Asian cooperation for you! The LG (Korean) unit, made in China, uses a big Panasonic (Japanese) chip - the MN103SD9GRAB, which if you look online you'll get of a lot of stuff like "Hong Kong Inventory" offering to sell you several hundred of the things, but nothing that resembles a datasheet. Suffice to say this one chip is the heart of the DVD writer. SATA at one end, burny-uppy laser at the other. And a decent amount of smarts in between.

I'm not going to strip down the optical unit, as it's fragile and I might still want to use this device. Here's a photo.

The eye of Sauron.

However, in answer to the question... it's a laptop drive with a USB interface stuck to the back, placed into a fancy looking box.

You're welcome. ☺

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Anon, 24th November 2023, 12:15

Ah yes, the old USB optical drive hack.    I changed my PC a bit back. My previous one (a home-built AMD A6 quad-core) had a Pioneer BD-RE drive fitted, which would also read and write DVDs and CDs of course.    The new one didn't have space for an optical drive. Or any drive, come to that. It was a Gigabyte Brix platform, so tiny base unit with no internal drives, OS installed from USB and all software installed from USB or network. But I wanted a blu-ray drive.    I had an old SCSI case kicking around that I used back when I had an A5000 with a SCSI CD-ROM drive. The case was empty as I'd moved the drive into the RISC PC when I upgraded. So... I undid the two Centronics connectors and took them out, picked up a USB3 to SATA interface for about £8 from Amazon, attached it to the back of the Blu-Ray writer and mounted it in the SCSI case, threading the cables out through where the Centronics ports had been.    It works perfectly. Meaning I can still rip DVDs and blu-rays as well as CDs.    I'd been looking at external blu-ray writers (around £70!) before I came up with this brainwave of re-purposing the old SCSI external case and re-using the Pioneer BD-RE drive.    So yes, most of the external drives are just standard SATA with a SATA-USB interface.

David Pilling, 24th November 2023, 12:52

I always wondered what was in the large capacity portable USB hard discs that have been my backup of choice in recent years. I have moved to SSD, connecting one of those to the PI, I use a standalone SATA to USB adaptor, a sub-10 quid device that is not much more to look at than a lead with two connectors.  The SSD to USB adaptors are the greatest thing since sliced bread, take any SATA drive and plug it into a USB port. Makes backups and moving stuff to a new machine easy.  All this is ancient history, latest SSDs I got were NVMe. Similar adaptors for USB or SATA are available.

A tree-dwelling mammal, 25th November 2023, 13:58

I picked up a USB to ATA interface a few years back when I'd just got my first Pi (V1 model B), installed RISC OS on the SD card and wanted to use it to pull some old files off the hard disks from my RISC PC (which had suffered from the kamikaze battery problem). Managed to safely copy both of the "huge" 1.2GB disks across, 'Wallace' (drive 5) and 'Gromit' (drive 4). The SCSI disks 'Shaun', 'Feathers' and 'Preston' all had to wait until I managed to dig out a working RPC and move the SCSI card from the dead machine into the working one.    (And yes, one of my A5000s had disks named 'Beavis' and 'Butt-head'. Another A5000 had disks 'Pinky' and 'Brain'. It was kinda fun back then.)    Rick - is this new name better? Or is it a bit too literal? ;-)

jgh, 26th November 2023, 08:24

I find it very slightly amazing that the 8051 is still going strong in commercial products. I brushed up on the coding a couple of years ago after having seen it in quite a few job adverts.

jgh, 26th November 2023, 08:26

My A5000's main drive is boringly called.... A5000 ;)

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