For the longest time, people thought that humans could not run a mile in less than four minutes. Then, in 1954, [Sir Roger Bannister] beat that perception, and shortly thereafter, once he showed it was possible, many other runners were able to achieve this also. The same is being said now about the IBM Watson computer which appeared this week against two human contestants on Jeopardy!
Often, when a company demonstrates new techology, these are prototypes not yet ready for commercial deployment until several years later. IBM Watson, however, was made mostly from commercially available hardware, software and information resources. As several have noted, the 1TB of data used to search for answers could fit on a single USB drive that you buy at your local computer store.
But could you fit an entire Watson in your basement? The IBM Power 750 servers used in IBM Watson earned the [EPA Energy Star] rating, and is substantially [more energy-efficient than comparable 4-socket x86, Itanium, or SPARC servers]. However, having ninety of them in your basement would drive up your energy bill.
Take a look at the [IBM Research Team] to determine how the project was organized. Let's decide what we need, and what we don't in our Watson Jr.:
|Role:||Do we need it for Watson Jr.?|
|Team Lead||Yes, That's you. Assuming this is a one-person project, you will act as Team Lead.|
|Algorithms||Yes, I hope you know computer programming!|
|Game Strategy||No, since Watson Jr. won't be appearing on Jeopardy, we won't need strategy on wager amounts for the Daily Double, or what clues to pick next. Let's focus merely on a computer that can accept a question in text, and provide an answer back, in text.|
|Systems||Yes, this team focused on how to wire all the hardware together. We need to do that, although Watson Jr. will have fewer components.|
|Speech Synthesis||Optional. For now, let's have Watson Jr. just return its answer in plain text. Consider this Extra Credit after you get the rest of the system working. Consider using [eSpeak], [FreeTTS], or the Modular Architecture for Research on speech sYnthesis [MARY] Text-to-Speech synthesizers. |
|Annotations||Yes, I will explain what this is, and why you need it.|
|Information Sources||Yes, we will need to get information for Watson Jr. to process|
|Question Parsing||Yes, this team developed a system for parsing the question being asked, and to attach meaning to the different words involved.|
|Search Optimization||No, this team focused on making IBM Watson optimized to answer in 3 seconds or less. We can accept a slower response, so we can skip this.|
|Project Management||Yes, even for a one-person project, having a little "project management" never hurt anyone. I highly recommend the book [Getting Things Done: The Art of Stress-Free Productivity] by David Allen].|
(Disclaimer: As with any Do-It-Yourself (DIY) project, I am not responsible if you are not happy with your Watson Jr. I am basing the approach on what I read from publicly available sources, and my work in Linux, supercomputers, XIV, and SONAS. For our purposes, Watson Jr. is based entirely on commodity hardware, open source software, and publicly available sources of information. Your Watson Jr. will certainly not be as fast or as clever as the IBM Watson you saw on television.)
- Step 1: Buy the Hardware
Supercomputers are built as a cluster of identical compute servers lashed together by a network. You will be installing Linux on them, so if you can avoid paying extra for Microsoft Windows, that would save you some money. Here is your shopping list:
- Three x86 hosts, with the following:
- 64-bit quad-core processor, either Intel-VT or AMD-V capable,
- 8GB of DRAM, or larger
- 300GB of hard disk, or larger
- CD or DVD Read/Write drive
- 1GbE Ethernet
- Computer Monitor, mouse and keyboard
- Ethernet 1GbE 4-port hub, and appropriate RJ45 cables
- Surge protector and Power strip
- Local Console Monitor (LCM) 4-port switch (formerly known as a KVM switch) and appropriate cables. This is optional, but will make it easier during the development. Once your Watson Jr. is operational, you will only need the monitor and keyboard attached to one machine. The other two machines can remain "headless" servers.
- Step 2: Establish Networking
IBM Watson used Juniper switches running at 10Gbps Ethernet (10GbE) speeds, but was not connected to the Internet while playing Jeopardy! Instead, these Ethernet links were for the POWER7 servers to talk to each other, and to access files over the Network File System (NFS) protocol to the internal customized SONAS storage I/O nodes.
The Watson Jr. will be able to run "disconnected from the Internet" as well. However, you will need Internet access to download the code and information sources. For our purposes, 1GbE should be sufficient. Connect your Ethernet hub to your DSL or Cable modem. Connect all three hosts to the Ethernet switch. Connect your keyboard, video monitor and mouse to the LCM, and connect the LCM to the three hosts.
- Step 3: Install Linux and Middleware
To say I use Linux on a daily basis is an understatement. Linux runs on my Android-based cell phone, my laptop at work, my personal computers at home, most of our IBM storage devices from SAN Volume Controller to XIV to SONAS, and even on my Tivo at home which recorded my televised episodes of Jeopardy!
For this project, you can use any modern Linux distribution that supports KVM. IBM Watson used Novel SUSE Linux Enterprise Server [SLES 11]. Alternatively, I can also recommend either Red Hat Enterprise Linux [RHEL 6] or Canonical [Ubuntu v10]. Each distribution of Linux comes in different orientations. Download the the 64-bit "ISO" files for each version, and burn them to CDs.
- Graphical User Interface (GUI) oriented, often referred to as "Desktop" or "HPC-Head"
- Command Line Interface (CLI) oriented, often referred to as "Server" or "HPC-Compute"
- Guest OS oriented, to run in a Hypervisor such as KVM, Xen, or VMware. Novell calls theirs "Just Enough Operating System" [JeOS].
For Watson Jr., I have chosen a [multitier architecture], sometimes referred to as an "n-tier" or "client/server" architecture.
- Host 1 - Presentation Server
For the Human-Computer Interface [HCI], the IBM Watson received categories and clues as text files via TCP/IP, had a [beautiful avatar] representing a planet with 42 circles streaking across in orbit, and text-to-speech synthesizer to respond in a computerized voice. Your Watson Jr. will not be this sophisticated. Instead, we will have a simple text-based Query Panel web interface accessible from a browser like Mozilla Firefox.
Host 1 will be your Presentation Server, the connection to your keyboard, video monitor and mouse. Install the "Desktop" or "HPC Head Node" version of Linux. Install [Apache Web Server and Tomcat] to run the Query Panel. Host 1 will also be your "programming" host. Install the [Java SDK] and the [Eclipse IDE for Java Developers]. If you always wanted to learn Java, now is your chance. There are plenty of books on Java if that is not the language you normally write code.
While three little systems doesn't constitute an "Extreme Cloud" environment, you might like to try out the "Extreme Cloud Administration Tool", called [xCat], which was used to manage the many servers in IBM Watson.
- Host 2 - Business Logic Server
Host 2 will be driving most of the "thinking". Install the "Server" or "HPC Compute Node" version of Linux. This will be running a server virtualization Hypervisor. I recommend KVM, but you can probably run Xen or VMware instead if you like.
- Host 3 - File and Database Server
Host 3 will hold your information sources, indices, and databases. Install the "Server" or "HPC Compute Node" version of Linux. This will be your NFS server, which might come up as a question during the installation process.
Technically, you could run different Linux distributions on different machines. For example, you could run "Ubuntu Desktop" for host 1, "RHEL 6 Server" for host 2, and "SLES 11" for host 3. In general, Red Hat tries to be the best "Server" platform, and Novell tries to make SLES be the best "Guest OS".
My advice is to pick a single distribution and use it for everything, Desktop, Server, and Guest OS. If you are new to Linux, choose Ubuntu. There are plenty of books on Linux in general, and Ubuntu in particular, and Ubuntu has a helpful community of volunteers to answer your questions.
- Step 4: Download Information Sources
You will need some documents for Watson Jr. to process.
IBM Watson used a modified SONAS to provide a highly-available clustered NFS server. For Watson Jr., we won't need that level of sophistication. Configure Host 3 as the NFS server, and Hosts 1 and 2 as NFS clients. See the [Linux-NFS-HOWTO] for details. To optimize performance, host 3 will be the "official master copy", but we will use a Linux utility called rsync to copy the information sources over to the hosts 1 and 2. This allows the task engines on those hosts to access local disk resources during question-answer processing.
We will also need a relational database. You won't need a high-powered IBM DB2. Watson Jr. can do fine with something like [Apache Derby] which is the open source version of IBM CloudScape from its Informix acquisition. Set up Host 3 as the Derby Network Server, and Hosts 1 and 2 as Derby Network Clients. For more about structured content in relational databases, see my post [IBM Watson - Business Intelligence, Data Retrieval and Text Mining].
Linux includes a utility called wget which allows you to download content from the Internet to your system. What documents you decide to download is up to you, based on what types of questions you want answered. For example, if you like Literature, check out the vast resources at [FullBooks.com]. You can automate the download by writing a shell script or program to invoke wget to all the places you want to fetch data from. Rename the downloaded files to something unique, as often they are just "index.html". For more on wget utility, see [IBM Developerworks].
- Step 5: The Query Panel - Parsing the Question
Next, we need to parse the question and have some sense of what is being asked for. For this we will use [OpenNLP] for Natural Language Processing, and [OpenCyc] for the conceptual logic reasoning. See Doug Lenat presenting this 75-minute video [Computers versus Common Sense]. To learn more, see the [CYC 101 Tutorial].
Unlike Jeopardy! where Alex Trebek provides the answer and contestants must respond with the correct question, we will do normal Question-and-Answer processing. To keep things simple, we will limit questions to the following formats:
- Who is ...?
- Where is ...?
- When did ... happen?
- What is ...?
- Which ...?
Host 1 will have a simple Query Panel web interface. At the top, a place to enter your question, and a "submit" button, and a place at the bottom for the answer to be shown. When "submit" is pressed, this will pass the question to "main.jsp", the Java servlet program that will start the Question-answering analysis. Limiting the types of questions that can be posed will simplify hypothesis generation, reduce the candidate set and evidence evaluation, allowing the analytics processing to continue in reasonable time.
- Step 6: Unstructured Information Management Architecture
The "heart and soul" of IBM Watson is Unstructured Information Management Architecture [UIMA]. IBM developed this, then made it available to the world as open source. It is maintained by the [Apache Software Foundation], and overseen by the Organization for the Advancement of Structured Information Standards [OASIS].
Basically, UIMA lets you scan unstructured documents, gleam the important points, and put that into a database for later retrieval. In the graph above, DBs means 'databases' and KBs means 'knowledge bases'. See the 4-minute YouTube video of [IBM Content Analytics], the commercial version of UIMA.
Starting from the left, the Collection Reader selects each document to process, and creates an empty Common Analysis Structure (CAS) which serves as a standardized container for information. This CAS is passed to Analysis Engines , composed of one or more Annotators which analyze the text and fill the CAS with the information found. The CAS are passed to CAS Consumers which do something with the information found, such as enter an entry into a database, update an index, or update a vote count.
(Note: This point requires, what we in the industry call a small matter of programming, or [SMOP]. If you've always wanted to learn Java programming, XML, and JDBC, you will get to do plenty here. )
If you are not familiar with UIMA, consider this [UIMA Tutorial].
- Step 7: Parallel Processing
People have asked me why IBM Watson is so big. Did we really need 2,880 cores of processing power? As a supercomputer, the 80 TeraFLOPs of IBM Watson would place it only in 94th place on the [Top 500 Supercomputers]. While IBM Watson may be the [Smartest Machine on Earth], the most powerful supercomputer at this time is the Tianhe-1A with more than 186,000 cores, capable of 2,566 TeraFLOPs.
To determine how big IBM Watson needed to be, the IBM Research team ran the DeepQA algorithm on a single core. It took 2 hours to answer a single Jeopardy question! Let's look at the performance data:
|Element||Number of cores||Time to answer one Jeopardy question|
|Single core||1||2 hours|
|Single IBM Power750 server||32||< 4 minutes|
|Single rack (10 servers)||320||< 30 seconds|
|IBM Watson (90 servers)||2,880||< 3 seconds|
The old adage applies, [many hands make for light work]. The idea is to divide-and-conquer. For example, if you wanted to find a particular street address in the Manhattan phone book, you could dispatch fifty pages to each friend and they could all scan those pages at the same time. This is known as "Parallel Processing" and is how supercomputers are able to work so well. However, not all algorithms lend well to parallel processing, and the phrase [nine women can't have a baby in one month] is often used to remind us of this.
Fortuantely, UIMA is designed for parallel processing. You need to install UIMA-AS for Asynchronous Scale-out processing, an add-on to the base UIMA Java framework, supporting a very flexible scale-out capability based on JMS (Java Messaging Services) and ActiveMQ. We will also need Apache Hadoop, an open source implementation used by Yahoo Search engine. Hadoop has a "MapReduce" engine that allows you to divide the work, dispatch pieces to different "task engines", and the combine the results afterwards.
Host 2 will run Hadoop and drive the MapReduce process. Plan to have three KVM guests on Host 1, four on Host 2, and three on Host 3. That means you have 10 task engines to work with. These task engines can be deployed for Content Readers, Analysis Engines, and CAS Consumers. When all processing is done, the resulting votes will be tabulated and the top answer displayed on the Query Panel on Host 1.
- Step 8: Testing
To simplify testing, use a batch processing approach. Rather than entering questions by hand in the Query Panel, generate a long list of questions in a file, and submit for processing. This will allow you to fine-tune the environment, optimize for performance, and validate the answers returned.
There you have it. By the time you get your Watson Jr. fully operational, you will have learned a lot of useful skills, including Linux administration, Ethernet networking, NFS file system configuration, Java programming, UIMA text mining analysis, and MapReduce parallel processing. Hopefully, you will also gain an appreciation for how difficult it was for the IBM Research team to accomplish what they had for the Grand Challenge on Jeopardy! Not surprisingly, IBM Watson is making IBM [as sexy to work for as Apple, Google or Facebook], all of which started their business in a garage or a basement with a system as small as Watson Jr..
technorati tags: IBM, Watson, Jeopardy, Challenge, POWER7, EPA, Energy Star, RHEL, SLES, Ubuntu, Linux, UIMA, Hadoop, MapReduce, KVM, DeepQA, Eric Brown
Since so many personal and corporate users are still on [Windows XP], Microsoft announced that it would provide [Extended Support until 2014]. A ComputerWorld article back in 2007 offered tips on [How to make Windows XP last for the next seven years]. From May 2009 to April 2014, all support is fee-based and non-security hotfixes are produced only for corporate customers.
If we have learned anything from last decade's Y2K crisis, is that we should not wait for the last minute to take action. Now is the time to start thinking about weaning ourselves off Windows XP. IBM has 400,000 employees, so this is not a trivial matter.
Already, IBM has taken some bold steps:
Last July, IBM announced that it was switching from Internet Explorer (IE6) to [Mozilla Firefox as its standard browser]. IBM has been contributing to this open source project for years, including support for open standards, and to make it [more accessible to handicapped employees with visual and motor impairments]. I use Firefox already on Windows, Mac and Linux, so there was no learning curve for me. Before this announcement, if some web-based application did not work on Firefox, our Helpdesk told us to switch back to Internet Explorer. Those days are over. Now, if a web-based application doesn't work on Firefox, we either stop using it, or it gets fixed.
IBM also announced the latest [IBM Lotus Symphony 3] software, which replaces Microsoft Office for Powerpoint, Excel and Word applications. Symphony also works across Mac, Windows and Linux. It is based on the OpenOffice open source project, and handles open-standard document formats (ODF). Support for Microsoft Office 2003 will also run out in the year 2014, so moving off proprietary formats to open standards makes sense.
I am not going to wait for IBM to decide how to proceed next, so I am starting my own migrations. In my case, I need to do it twice, on my IBM-provided laptop as well as my personal PC at home.
- IBM-provided laptop
Last summer, IBM sent me a new laptop, we get a new one every 3-4 years. It was pre-installed with Windows XP, but powerful enough to run a 64-bit operating system in the future. Here are my series of blog posts on that:
I decided to try out Red Hat Enterprise Linux 6.1 with its KVM-based Red Hat Enterprise Virtualization to run Windows XP as a guest OS. I will try to run as much as I can on native Linux, but will have Windows XP guest as a next option, and if that still doesn't work, reboot the system in native Windows XP mode.
Here's is how I have configured my laptop:
|/dev/sda1||35GB||NTFS||C:||Windows XP SP3 operating system and programs|
|/dev/sda2||15GB||ext4||/(root)||Ubuntu Desktop 10.10, SystemRescueCD, Clonezilla, Parted Magic|
|/dev/sda3||55GB||ext4||/(root)||RHEL 6.1 with KVM to run Windows XP as guest OS|
|/dev/sda6||130GB||NTFS||D:||My Documents, Lotus Notes and other data|
|/dev/sda7||70GB||NTFS||E:||Extras and Archives|
Basically, this is a multi-boot system. I use Ubuntu to hold all my Linux utilities, including [SystemRescueCD], [Clonezilla], and [Parted Magic]. The new [Grub2 loader] makes this easy.
Here is what my initial boot screen looks like:
So far, I am pleased that I can do nearly everything my job requires natively in Red Hat Linux, including accessing my Lotus Notes for email and databases, edit and present documents with Lotus Symphony, and so on. I have made RHEL 6.1 my default when I boot up. Setting up Windows XP under KVM was relatively simple, involving an 8-line shell script and 54-line XML file. Here is what I have encountered:
- We use a wonderful tool called "iSpring Pro" which merges Powerpoint slides with voice recordings for each page into a Shockwave Flash video. I have not yet found a Linux equivalent for this yet.
- To avoid having to duplicate files between systems, I use instead symbolic links. For example, my Lotus Notes local email repository sits on D: drive, but I can access it directly with a link from /home/tpearson/notes/data.
- While my native Ubuntu and RHEL Linux can access my C:, D: and E: drives in native NTFS file system format, the irony is that my Windows XP guest OS under KVM cannot. This means moving something from NTFS over to Ext4, just so that I can access it from the Windows XP guest application.
- For whatever reason, "Password Safe" did not run on the Windows XP guest. I launch it, but it takes forever to load and never brings up the GUI. Fortunately, there is a Linux version [MyPasswordSafe] that seems to work just fine to keep track of all my passwords.
- Personal home PC
My Windows XP system at home gave up the ghost last month, so I bought a new system with Windows 7 Professional, quad-core Intel processor and 6GB of memory. There are [various editions of Windows 7], but I chose Windows 7 Professional to support running Windows XP as a guest image.
Here's is how I have configured my personal computer:
|/dev/sda1||104MB||NTFS||C:||Windows 7 Loader|
|/dev/sda2||10GB||ext4||/(root)||Ubuntu Desktop 10.10, SystemRescueCD, Clonezilla, Parted Magic|
|/dev/sda6||60GB||NTFS||C:||Windows 7 OS and programs|
|/dev/sda7||230GB||NTFS||D:||My Documents, Lotus Notes and other data|
|/dev/sda8||250GB||NTFS||E:||Extras and Archives|
I actually found it more time-consuming to implement the "Virtual PC" feature of Windows 7 to get Windows XP mode working than KVM on Red Hat Linux. I am amazed how many of my Windows XP programs DO NOT RUN AT ALL natively on Windows 7. I now have native 64-bit versions of Lotus Notes and Symphony 3, which will do well enough for me for now.
I went ahead and put Red Hat Linux on my home system as well, but since I have Windows XP running as a guest under Windows 7, no need to duplicate KVM setup there. At least if I have problems with Windows 7, I can reboot in RHEL6 Linux at home and use that for Linux-native applications.
Hopefully, this will position me well in case IBM decides to either go with Windows 7 or Linux as the replacement OS for Windows XP.
technorati tags: IBM, Windows, Windows XP, Windows 7, Linux, Ubuntu, RedHat, RHEL, RHEL6, Lotus, Lotus Notes, Lotus Symphony
Are you tired of hearing about Cloud Computing without having any hands-on experience? Here's your chance. IBM has recently launched its IBM Development and Test Cloud beta. This gives you a "sandbox" to play in. Here's a few steps to get started:
- Go to the [IBM Developer & Test in the IBM Cloud beta] dashboard and register for an account. This can be your email address and your own password. You can watch the helpful videos.
- Generate a "key pair". There are two keys. A "public" key that will reside in the cloud, and a "private" key that you download to your personal computer. Don't lose this key.
- Request an IP address. This step is optional, but I went ahead and got a static IP, so I don't have to type in long hostnames like "vm353.developer.ihost.com".
- Request storage space. Again, this step is optional, but you can request a 50GB, 100GB and 200GB LUN. I picked a 200GB LUN. Note that each instance comes with some 10 to 30GB storage already. The advantage to a storage LUN is that it is persistent, and you can mount it to different instances.
- Start an "instance". An "instance" is a virtual machine, pre-installed with whatever software you chose from the "asset catalog". These are Linux images running under Red Hat Enterprise Virtualization (RHEV) which is based on Linux's kernel virtual machine (KVM). When you start an instance, you get to decide its size (small, medium, or large), whether to use your static IP address, and where to mount your storage LUN. On the examples below, I had each instance with a static IP and mounted the storage LUN to /media/storage subdirectory. The process takes a few minutes.
- Download some programs on your personal computer. I downloaded an SSH client called [PuTTY] and an [NX client from NoMachine].
So, now that you are ready to go, what instance should you pick from the catalog? Here are three examples to get you started:
- IBM WebSphere sMASH Application Builder
- Base OS server to run LAMP stack
Next, I decided to try out one of the base OS images. There are a lot of books on Linux, Apache, MySQL and PHP (LAMP) which represents nearly 70 percent of the web sites on the internet. This instance let's you install all the software from scratch. Between Red Hat and Novell SUSE distributions of Linux, Red Hat is focused on being the Hypervisor of choice, and SUSE is focusing on being the Guest OS of choice. Most of the images on the "asset catalog" are based on SLES 10 SP2. However, there was a base OS image of Red Hat Enterprise Linux (RHEL) 5.4, so I chose that.
To install software, you either have to find the appropriate RPM package, or download a tarball and compile from source. To try both methods out, I downloaded tarballs of Apache Web Server and PHP, and got the RPM packages for MySQL. If you just want to learn SQL, there are instances on the asset catalog with DB2 and DB2 Express-C already pre-installed. However, if you are already an expert in MySQL, or are following a tutorial or examples based on MySQL from a classroom textbook, or just want a development and test environment that matches what your company uses in production, then by all means install MySQL.
This is where my SSH client comes in handy. I am able to login to my instance and use "wget" to fetch the appropriate files. An alternative is to use "SCP" (also part of PuTTY) to do a secure copy from your personal computer up to the instance. You will need to do everything via command line interface, including editing files, so I found this [VI cheat sheet] useful. I copied all of the tarballs and RPMs on my storage LUN ( /media/storage ) so as not to have to download them again.
Compiling and configuring them is a different matter. By default, you login as an end user, "idcuser" (which stands for IBM Developer Cloud user). However, sometimes you need "root" level access. Use "sudo bash" to get into root level mode, and this allows you to put the files where they need to be. If you haven't done a configure/make/make install in awhile, here's your chance to relive those "glory days".
In the end, I was able to confirm that Apache, MySQL and PHP were all running correctly. I wrote a simple index.php that invoked phpinfo() to show all the settings were set correctly. I rebooted the instance to ensure that all of the services started at boot time.
- Rational Application Developer over VDI
This last example, I started an instance pre-installed with Rational Application Developer (RAD), which is a full Integrated Development Environment (IDE) for Java and J2EE applications. I used the "NX Client" to launch a virtual desktop image (VDI) which in this case was Gnome on SLES 10 SP2. You might want to increase the screen resolution on your personal computer so that the VDI does not take up the entire screen.
From this VDI, you can launch any of the programs, just as if it were your own personal computer. Launch RAD, and you get the familiar environment. I created a short Java program and launched it on the internal WebSphere Application Server test image to confirm it was working correctly.
If you are thinking, "This is too good to be true!" there is a small catch. The instances are only up and running for 7 days. After that, they go away, and you have to start up another one. This includes any files you had on the local disk drive. You have a few options to save your work:
- Copy the files you want to save to your storage LUN. This storage LUN appears persistent, and continues to exist after the instance goes away.
- Take an "image" of your "instance", a function provided in the IBM Developer and Test Cloud. If you start a project Monday morning, work on it all week, then on Friday afternoon, take an "image". This will shutdown your instance, and backup all of the files to your own personal "asset catalog" so that the next time you request an instance, you can chose that "image" as the starting point.
Another option is to request an "extension" which gives you another 7 days for that instance. You can request up to five unique instances running at the same time, so if you wanted to develop and test a multi-host application, perhaps one host that acts as the front-end web server, another host that does some kind of processing, and a third host that manages the database, this is all possible. As far as I can tell, you can do all the above from either a Windows, Mac or Linux personal computer.
Getting hands-on access to Cloud Computing really helps to understand this technology!
technorati tags: , IBM, Development, Test, Cloud, WebSphere, sMASH, WaveMaker, LAMP, Linux, Apache, MySQL, PHP, Rational, RAD, VDI, , RHEL, RHEV, KVM, SUSE, SLES, Novell, NX, PuTTY, SSH