Get Microsoft Windows 8.1 installation media (ISO) for offline update or fresh installation

I just found something I thought I should pass along. Sure, it’s only for the desktop OS, but many if not all of us in this line of work use one. (If you don’t use Windows, or don’t support your own workstation, maybe sharing the info can gain you some brownie points with folks who do.) It was not readily apparent in my searching the web, either: Microsoft has made Windows 8.1 (or 8.1 Pro) installation bits available for download for you and me– and yes, you can install from that media using your retail Windows 8 or Windows 8 Pro Product Key.

Not so long ago, one would have had to install Windows 8, then get online for hours to patch it and then upgrade to Windows 8.1. For me, this got in the way of having what I like to call a “gold copy” of a system build. IMO, being networked for so long increases risk exposure, reduces trustworthiness, and otherwise tarnishes the golden-ness of a system build image. What about doing a Windows 8.1 offline update? Keep reading…

How to get Linux hosts with DHCP IP addresses to show up in Microsoft DNS automatically

This blog post outlines a little trick we use to get Linux-based hosts on a network to show up in Microsoft-based DNS… automagically. This self-registration with DNS usually “just works” in a homogeneous Windows network (famous last words!)– so many folks take it for granted until they need something from the Linux ecosystem. Without setting this up, your options are either A) refer to said machines by IP address only, or B) manually add their hostnames and IPs into DNS, and manually keep those records updated. Keep reading…

What the Heck is Constant Folding?

Constant Folding is the term used when SQL Server query optimizer evaluates an expression or expressions BEFORE the query is compiled. For example, the following query would undergo constant folding by the optimizer before compilation:

SELECT COUNT(1) FROM dbo.SampleTable WHERE IDColumn = 5 + 7

The expression “5 + 7” is evaluated to “12” before the query is compiled. Constant folding happens for a limited number of expressions. Generally speaking, constant folding occurs for the following types of expressions:

1. Arithmetic expressions containing only constants (and no variables or parameters)

2. Logical expressions containing only constants, such as 1=1 and 1>0

3. Built-in deterministic functions whose inputs rely solely on provided values, without depending on any external context, such as database settings, encryption keys, environment variables, etc.

When possible, construct your T-SQL code in such a way that the optimizer can make use of constant folding. This will alleviate the need for the optimizer to repeatedly evaluate the expression at run time. It will also allow the cardinality estimator to more accurately predict the size of the result set.

For further reading, I highly suggest reading the TechNet article on Constant Folding. You can find some related information in the Forced Parameterization TechNet article here.

Happy coding!