Blog

High Speed Phone/Data Services

By gilbert on April 23, 2010

The FCC has proposed a target of delivering 100 megabit per second Internet service to much of the US. Although this might be achieved using Cable TV or new fiber optic cables to every house, recent developments from Bell Labs suggest that the target can also be met with good old copper telephone wire. This paper describes the history and future of what is known as "telephone twisted pair", the copper telephone wire you have in your house and see on telephone poles outside your window.

<--break->

Disk Block Size

By gilbert on March 10, 2010

New hard drives are increasing their sector size (the smallest unit of data that you can physically read or write to the disk) from 512 bytes to 4096 bytes. This is required to allow disks larger than 2 terabytes. You can emulate the old sector size, but at a loss of performance. Linux and Mac systems are already optimized for the larger sector size, but Windows 7 is the Microsoft system with best support.

Meanwhile, SSDs have a physical unit of 512K (a half megabyte). This is the smallest block of data that you can erase, and you have to erase data before you can rewrite it. This poses a different block size problem for the OS, filesystem, and application.

I've Looked at Clouds from Both Sides Now

By gilbert on February 28, 2010

The new big thing from Microsoft is Azure, their view of "Cloud Computing". It is the new feature in Visual Studio 2010. It competes with other cloud services from Google and Amazon. This is all leading edge stuff. Right?

From SILT to the iPad

By gilbert on February 12, 2010

In the early 1970s the SHARE users group of IBM mainframe computers released a prediction about the future called the SILT report. They envisioned a transition where the operating system would become part of the microcode of the computer, leaving only the Application Programming Interface for customers. Today, this prediction may finally be coming true, at least on handheld devices.

A new direction in CPU design

By gilbert on February 12, 2010

An Intel research paper suggests a new approach to the circuit design of a CPU chip that might show up in future Intel products. Current systems have no internal error detection circuits, so they depend on wide margins of tolerence so that errors are very, very unlikely. Suppose, however, a future chip design adds internal error detection and correction to every CPU unit, and then runs the chip at higher speed or lower power that makes the now correctable errors much more likely now that they are safe.