## Friday, October 18, 2013

### colored blocks in Beamer

Update: see here for better ways.

The beauty of LaTeX is that you get the best possible typography while focusing on the content, without having to spend any cycles on the looks. For example, when you prepare a presentation, you just pick a theme and do your slides. If you do not like how they look, you change the theme. Consequently, the Beamer class manual just teaches you how to create the flow (overlays, etc.) of a presentation.

In the second part the Beamer manual gives in detail all the information on how to create a new template, but this is too much when you just need a small feature like colored blocks. This is something that usually does not occur in technical presentations, where there already is a specialized block machinery for theorems, examples, etc.

When you do presentations more related to technical marketing, you may want to use colored blocks, for example to clearly discriminate between pros and cons by using green respectively red boxes. Since it is not in the manual, here is how you do colored boxes. Essentially, you declare new block environments in the document preamble:

\newenvironment<>{problock}[1]{

\begin{actionenv}#2

\def\insertblocktitle{#1}

\par

\mode<presentation>{

\setbeamercolor{block title}{fg=white,bg=green!50!black}

\setbeamercolor{block body}{fg=black,bg=green!10}

\setbeamercolor{itemize item}{fg=red!20!black}

\setbeamertemplate{itemize item}[triangle]

}

\usebeamertemplate{block begin}}

{\par\usebeamertemplate{block end}\end{actionenv}}

\newenvironment<>{conblock}[1]{

\begin{actionenv}#2

\def\insertblocktitle{#1}

\par

\mode<presentation>{

\setbeamercolor{block title}{fg=white,bg=red!50!black}

\setbeamercolor{block body}{fg=black,bg=red!10}

\setbeamercolor{itemize item}{fg=green!20!black}

\setbeamertemplate{itemize item}[triangle]

}

\usebeamertemplate{block begin}}

{\par\usebeamertemplate{block end}\end{actionenv}}

The notation for banged color shades is as follows: 10% red is specified as red!10, while green!20!black means 20% green with 80% black.

In the document part, a SWOT matrix slide would then be specified as follows:

\begin{frame}{SWOT Matrix}

\begin{columns}[t]

\begin{column}{.5\textwidth}

\begin{problock}{\textsc{strengths}}

\begin{itemize}

\begin{itemize}

\item revenue: \$10 B \item market share: 70\% \end{itemize} \item Product \begin{itemize} \item 32-bit color \item written in OpenCL \end{itemize} \end{itemize} \end{conblock} \end{column} \begin{column}{.5\textwidth} \begin{conblock}{\textsc{weaknesses}} \begin{itemize} \item Business \begin{itemize} \item very expensive \item gold plating issues \end{itemize} \item Product \begin{itemize} \item requires at least 128 cores \item no gamut mapping \end{itemize} \end{itemize} \end{problock} \end{column} \end{columns} \begin{columns}[t] \begin{column}{.5\textwidth} \begin{problock}{\textsc{opportunities}} \begin{itemize} \item Business \begin{itemize} \item everybody wants color \item clouds love rainbows \end{itemize} \item Product \begin{itemize} \item cameras deliver 14 bits per pixel \item big data is pervasive \end{itemize} \end{itemize} \end{conblock} \end{column} \begin{column}{.5\textwidth} \begin{conblock}{\textsc{threats}} \begin{itemize} \item Business \begin{itemize} \item pursue low hanging fruit \item people do not care about color quality \end{itemize} \item Product \begin{itemize} \item competitors use CIELAB \item spectral is a new trend \end{itemize} \end{itemize} \end{problock} \end{column} \end{columns} \end{frame} ## Friday, October 11, 2013 ### now you can go paperless In 1945 Vannevar Bush proposed the Memex desk to store and hyperlink all our documents. In 1969 Jack Goldman from Xerox approached George Pake to set up PARC with the task of inventing the paperless office of the future. By the late 1980s, with Mark Weiser's System 33 project all pieces were available and integrated to realize the paperless office of the future, including mobile computing under the name of ubiquitous computing or ubicomp. The problem was that the computer hardware was still to far behind. A Dorado ran only at 1 MIPS and typically had 4 MB of RAM and an 80 MB disk, but its ECL technology sucked up 3 KW of power and the material cost$112K in today's dollars.

By the mid-1990s the hardware had become sufficiently powerful and cheap that people like Gary Starkweather and Bill Hewlett were able to digitize all their documents and live a paperless life, but not people like us.

For the rest of us the year to go completely digital is 2013. The current Xeon E5 chip-set offers up to 12 cores and 40 GB/s PCI express bandwidth to which you can add a terabyte of fast PCI Express flash storage for the operating system, the applications, and your indices. This is sufficient horsepower to manage, index, and transcode all your digital items.

For the digital items I had hinted at using green disks in the my previous post, but then I made a calculation and showed a picture indicating this might not be a good solution after all. Here is the solution.

In System 33 the documents were stored on file servers, which is still done today in commercial applications. But in the SOHO setting this quickly leads to the monstrosity shown in the last post's picture. Where is the sweet spot for storing our digital items?

An external disk is easy and cheap, because it relies on the PC to manage the disk. In the real world of ubicomp we have many different computing devices, so we need the flexibility of a server. The solution is to use a disk with a minimalistic server, a contraption called a NAS, for network attached storage.

Because the various ubicomp devices have different file systems and file protocols, a NAS will have its own system and then provide the various native interfaces. Typically, the NAS operating system is a bare-bones Linux with an ext4 file system. It will support the main file protocols NFS, CIFS, AFP, FTP, SSH, WebDAV, TLS, etc.

Since your digital items are valuable, you do not want to use a single disk, also because with a large amount of data, backups of shared disks no longer make sense (you still need to backup your own devices). The minimal configuration is to use two identical disk drives in RAID-1 configuration. You also want to have a second NAS on a different continent to which you trickle-charge your digital items.

The box in the picture above is a Synology DS212j, which uses a Marvell 6281 ARM core running at 1.2 GHz. The SoC also includes hardware encryption (yes, you should always encrypt all your data) and a floating point unit. The latter is important because many digital items these days are photographs and an FPU is absolutely necessary to create the thumbnails (for video, you want to do any transcoding on your desktop and store the bits so that they can be streamed directly).

The assembly in the picture comprises the NAS box with the mini-server in the enclosed bottom, a large fan, and the two red disks. On the right side (front) are the status lights and on the left side (back) are the Ethernet port, the power port, a USB port to back up the NAS' own software and data on a stick, and a USB port for a printer to share.

The box in the picture has 512 MB of x16 DDR3 DRAM, which is plenty to run a bare-bones Linux, including such things like a MySQL database to manage the NAS data and a web server to administer the system. You want to attach it to a 1 gbps Ethernet using Cat-6 cabling (but Cat-5e is sufficient for a small home like mine).

When being accessed, the NAS will consume 17.6W + 9W = 26.6W, but when there is no network activity, the disks will go in hibernation mode and the power consumption will drop to 5.5W + 0.8W = 6.3W (the first number is the mini-server, the second is for the disks). In other words, a capable SOHO NAS capable of storing and serving all your digital items uses power comparable to a light bulb. You do not need any special electric service to your garage.

As we have seen regarding the disk colors, you absolutely want a pair of red disks, i.e., two Western Digital WD40EFRX or two Seagate ST4000VN000-1H4168.

## Thursday, October 3, 2013

### disk service time

In the last post we saw how hard disk drives (HDD) are color coded. I hinted on how to choose the color of a HDD, suggesting that for the main disk a solid state drive (SSD) is actually a better choice, but I left things fuzzy. The reason is that there is no single metric, you have to determine what your work day looks like. Fortunately there is one thing that no longer is an issue: capacity.