Seagate Dockstar - Teardown

I ordered a Seagate Dockstar on ebay as a playground for some experimenting with OpenWrt. This device is particularly well-equipped compared to similar ARM-based NAS/routers with its 128MB DDR2 SDRAM and 256MB Flash. Sadly though, the original purpose of the Dockstar seems badly established: your local NAS can only be managed through a web interface on dockstar.pogoplug.com, with local management support completely missing. I am not really happy with this option as I do not believe that it is safe at all.

Nevertheless the hardware is a state-of-the-art ARM-based board equipped with 4 USB 2.0 ports and gigabit Ethernet interface and strong enough to even support standard linux distributions. Debian and Gentoo have already been successfully installed. 

The box itself is nicely designed, the board is in a modern-look minimalistic box. The miniUSB port on the fits in some Seagate's external harddrives, however some third party boxes can be used, too, it takes only a ruler to figure it out.

Important!

Before going any further: NEVER ever connect the Dockstar to a network with public internet access. According to many reports it tends to "phone home", that is making automated software updates. This is a problem because the ssh access gets disabled and only serial console remains. This actually happened to me so consider this issue confirmed! Preventive measures include either a separate switch or subnet dedicated to the device or manually disabling routing to Dockstar on the gateway.
Update: I managed to resolve the problem, ssh access is regained. For details, jump here.

An inside look

Anyway, let's look inside! The top part of the casing holds with eight claws (two each side). After popping it off, the connector of the top mini USB port has to be removed, and the entire PCB becomes accessible. Below there are the main circuits on the two sides of the PCB that I pinpointed and figured out their purpose. For everyone who likes to visualize things, I have  also spotted them on the high-res PCB photos.

Top layer:

• Marvell Kirkwood 88F6281 ARM926 compatible SoC;
• Nanya NT5TU64M16DG-AC 128MB DDR2 SDRAM;
• Two Marvell dual switching power supply circuits.

On this layer we also find the dual LED, the reset button and the UART/JTAG service header. The supply input is a standard single pin connector with the center pin positive and the shield negative. The factory provided external power supply brick outputs 12V 2A. The serial/JTAG header pitch is 2.0mm, a rarely used standard, however available at most distributors.

Bottom layer:

• Marvell Alaska 88E1116R Gigabit Ethernet PHY;
• Micron 29F2G08AAD 256MB Flash;
• Genesys GL850G 4way USB 2.0 hub;
• Atmel AT24C02B I2C EEPROM;
• Monolithic MP8708 switching power supply;
• Marvell 88PG8227 dual switching power supply.

HP 5036A Microprocessor Lab

I just got this machine possessed. It is a microprocessor demonstration board based on the Intel 8085 CPU meaning that it was built for educational use and to demonstrate the capabilities of Intel's early 8 bit CPUs. According to a very few information on the web it was produced from 1978 through the early 80's by Hewlett-Packard.

First impressions:

The nice leather briefcase makes the appearance really elegant, something that is missed from new and modern equipment. Also, push buttons are built for eternity, no lifetime by design.

Technical data:

Manufacturer: Hewlett-Packard;

CPU: NEC D8085AC (Intel 8085 compatible);

CPU clock: 2 MHz using external 4 MHz crystal;

ROM: 2 KB external  SY2316 (mapped from 0x0000 to 0x07FF);

RAM: 1 KB external 2xSY2114 (mapped from 0x0800 to 0x0BFF);

Keyboard: built-in hexadecimal keyboard plus additional function keys;

Display: 6 digit LED display;

I/O: one 8 bit port with LED indicators and DIP switches;

On-board speaker;

Additional jumpers are provided to simulate circuit failures.

Note: Regarding to the ROM and RAM chips, I could only recover the manufacturer called Synertek, which was founded in 1973, bought by Honeywell in 1979, and finally closed off in 1985. Some photo on their products can be found here.

Operation:

Upon a successful boot, the message "uLAb UP" is visible on the LED displays. Storing new programs in the RAM is possible using the push button interface. These among built-in code can be run by simply pressing "Fetch Address", setting the appropriate memory address and pressing "Run". Single line execution is also possible. This is a notable example for a compact yet powerful user interface from times before LCD/TFT displays.

In order to ease learning, several built-in demos are accessible. Notable examples are:

the Rocket Launcher demo on address 0x05F9;

Display test with moving pattern on address 0x055A;

Random Tone Generator on address 0x053E;

Stopwatch on address 0x0662.

The documentation is in fact fascinating: a 450 page book entitled Practical Microprocessor is included in the briefcase. This is not only a tutorial but a complete documentation including ROM listing, schematics and some brief datasheets as well.