Salary structure - multiple options

Instead of having single salary structure, we started offering multiple options to our new employees,

1. Pure stock option => X number of company shares.
2. Stock option (Major portion) + Cash amount (Minor portion) => X number of company shares + Y amount of cash.
3. Cash amount (Major portion) + Stock option (Minor portion) => Y amount of cash + X number of company shares.
4. Pure cash amount => Y amount of cash.

We also allowed him to switch to other option within three month from the joining date.

Primay key look up : NOSQL vs SQL

To demonstrate this usecase, we retrieve bunch of columns for a primary key. Typical SQL would be,

"SELECT COLUMN1, COLUMN2, COLUMN3 FROM TABLE WHERE PRIMARY_KEY={X}".

Lets analyze what happens when we execute above SQL,

1) Query passes through SQL engine.

a) Lexical analysis & Parsing of SQL statement (Exception will be raised if any syntax error found).

b) SQL optimization to choose optimal execution path for the statement.

2) Searching the index for primary key

Most databses store table indexs on tree structure. B+ tree is most commonly and widely used indexing structure. Even with, highly optimized B+ index structure, some form of tree search is required to locate the primary key.

3) Primary key is located, perform data retrieval.

Primary key is located, corresponding row is returned for that primary key.

Is SQL way of retrieving data based on primary key effective?. Lets see how we implement same usecase with NOSQL,

"GET [TABLE][PRIMARY_KEY]"

In NOSQL, primary key and corresponding columns are stored as Hash (key => primarykey, value => column values as string/jason). With NOSQL, looking up primary key is performed in constant time and there is no need for lexical analysis, parsing and optimization. Does this pattern sound familer?. Many large websites use MySQL with Memcached. Memcached will serve as in-memory NOSQL.

NOSQL is better for fast retrieval of data using primary key. MySQL + Memcached combination could be used to achieve the same.

Startup Quants

As an entrepreneur, one aspect that i enjoy quite often is quantification of various aspect of our business.

• What is the current valuation of our venture?
• How much money should we raise in this round?
• Should i go for fixed size equity round or convertible debt round?
• How much options should i grant to person 'x'?
• What does it take to recruit this interesting guy?
• Why do customer think product 'x' is better than product 'y'?
• How to price our products?
• Is it worth pursuing idea 'x'?
• ....... ........ .......

It is very unlikely that one will find optimal answer to these questions. Certainly there would be very subjective answers to few of these questions.

To find near optimal answers, you may take advise from peers, read about experience of others but it will be your own experiments that will give satisfying answers. My approach has been "Experiment at smaller scale, amplify if the experiment is successful, re-experiment incase of failure" (You should be shameless about your failures, iterate quickly & fail fast).

Beware, when things are incomprehensible, you will treat them as cheap or flout them or think they are magical.

Welcome aboard

Most corporates have some form of induction program to on-board new employees. Startup doesn't have time, energy & man power for such programs.

In corporate environment such program can't be avoided for various reasons,

1) In corporates, it is not uncommon to on-board large group ( > 5 employees) at a time, but in startups it is always cherry picking.

2) Corporates do recruitment based on profile matching and (try to) mould employees to their culture but startups put lot of emphasis on culture & passion while recruiting itself.

3) During induction program, corporates will show what makes their company a unique place to work. But startups count on new employee(s) to make their company unique.

4) In corporates, one should understand structure of the company to escalate issues and get things done. But in startups, things & structure would be fluid.

5) Corporates trust their process more than people, whereas startups trust their people most.

I have also seen backlash from employees when a company transform from startup stage to corporate stage (Things were not like this before, Do we really need a position to take care certain things? etc).

In our startup bitstat technologies, we have introduced "self-experiment-and-use-your-freetime" induction process for new employees. In this process they will execute their own idea, create a simple software product, try to market it and will share their experience with others.

Someday, our startup would be a corporate. But till that time, our experiments will continue.

Open Source Calendar Server

I was looking for open source calender server with CalDev support. I finally decided to go with "Darwin Calendar Server", that is being developed and maintained by Apple. Darwin calendar server is developed with Python. Here are the instructions to build darwin calendar server on ubuntu,

a) apt-get install following components, if you don't have it,

build-essential
python-openssl
python-xattr
python-zopeinterface
python-xml
ibkrb5-dev
krb5-config

b) Create empty directory, check out CalendarServer inside empty directory (while building, system will download number of other necessary libs inside empty directory you have created),

svn checkout http://svn.calendarserver.org/repository/calendarserver/CalendarServer/trunk CalendarServer

c) Enable extended attributes for the filesystem (CalendarServer expects extended attribute enabled file system for storing calendar data),

edit, /etc/fstab and add user_xattr

Here is how my "/etc/fstab" looks after adding user_xattr,

UUID=2594fb7b-cb60-490c-8d08-1fbee11f1e5f / ext3 relatime,errors=remount-ro,user_xattr 0 1

d) Activate fstab changes, with 'mount -o remount /<mountpoint>'

e) To build CalendarServer, follow the instructions listed at,
http://trac.calendarserver.org/wiki/QuickStart

f) If everything goes fine, open browser with http://localhost:8008/calendars/users/admin/calendar (If you are challenged by security realm, enter admin for both username and password). You should see admin's calendar listing

g) You may use any calendar client that supports "CalDev" to access your calendar. If you plan to use sunbird as your client, follow the instructions at
http://trac.calendarserver.org/wiki/Sunbird

Register VMs : Rise of the machines

I am currently designing and implementing small language with in-built concurrency for experimental/learning purpose. I decided to go with virtual machine approach, but when we implement a virtual machine, we hit by a long-running question in the design of virtual machines, whether to go with stack architecture or with register architecture?

Many of virtual machines are implemented with stack architecture.

Stack based VMs:

• The Java Virtual Machine.
• .NET CLR
• Perl 5 virtual machine.
• SQLite Virtual Database Engine.

There is lot of interest in implementing VM based on register architecture too and practical register based VMs are started emerging.

Register based VMs:

• Parrot VM - http://en.wikipedia.org/wiki/Parrot_virtual_machine
• Android Dalvik VM - http://en.wikipedia.org/wiki/Dalvik_virtual_machine
• Webkit Javascript VM - http://webkit.org/blog/189/announcing-squirrelfish/

I decided to go with register based VM, thought of below two options and decided to go with first.

1) Implementing my register based VM in C

2) Implementing my register based VM in Java (Hey, java is improving and sun is adding multi language support and it is open!!!, so why not?) - In this case my VM itself interpreted on stack based JVM!!!

Magic of Multilanguage Environment

We need to create methods at runtime (say, based on some user input we need to construct an behavior in the form of methods) and associate/execute that methods in the context of particular existing object instance. How could we achieve this in Java?

1) Use features of mlvm. Currently it is in prototype stage. So we may have to wait for some time before being available as part of standard distribution.

2) We could use any of byte code engineering libraries and include a method in the class at runtime. But we are trying to include a method for a particular object instance of the class. Not in the class itself.

Hey, Javacript/Ruby very much allow adding new methods to a particular instance and good news is that we have matured Javascript (Rhino) and Ruby (JRuby) implementations in Java. You may be aware that Rhino javascript implementation is included as part of standard java 6 distribution. With the help of Rhino engine, we could take advantage of power of javascript and implement our scenario.

Include JDK_6_HOME/bin in your path.
Type jrunscript in command prompt.

var fr = new javax.swing.JFrame()
fr.title = "My Title"
fr.setSize(200, 200)
fr.show()

var fn_title = function(title_text) {this.title = title_text}
fn_title.call(fr, "My New Title")

"fn_title" is the method, that we have associated with "JFrame" instance "fr"

PS: Rhino engine is written in Java. How easy to simulate above behavior with our own java classes and byte code engineering? Look at these slides for answer.