My Sys Admin Magazine Articles Now On-line

CMP Media's Sys Admin Magazine, the #1 UNIX and Linux magazine in print circulation, has now made all of my past articles available on-line, and no longer just the ones that were "web features." For easier browsing, I have provided a direct index to any associated figures, listings, sidebars and/or tables for each article.

An index with abstract in reverse chronology ...

2005 September
Dissecting Virtual Tape Libraries (VTLs)

• Figure 1: Centralized, real-time tape backup
  
• Figure 2: Centralized, buffered tape backup
  
• Figure 3: Centralized, near-line disk + tape backup
  
• Table 1: Tape and disk media attributes
  
• Sidebar: Near-line enterprise disk
  
• Table 2: Enterprise v. commodity v. near-line disk
  

For a company that will never have a data loss event, backup is optional. For companies that will experience a data loss event, recovery is not optional. So, invariably, backup of any and all data that may need to be recovered is not optional. Backup strategies are still widely debated, with many beginning to claim tape is a legacy solution that can and should be completely replaced by disk. Keeping recovery clearly in mind, while disk may solve many backup-time issues, disk still has serious environmental, longevity, and portability issues.

2005 February
Licensing Risks, Not Revolutions: Part II

• Figure 1: Unmaintainable standards or source results in Hostageware
  

Part I of this article focused on redefining software licenses beyond the one-dimensional, non-descriptive values of "open" and "closed" (proprietary). It expanded the categorizations, applying the values to axes of "source code" and "standards compliance."

NOTE: These articles were hastily done (per Editor request for copy in these two issues), and my last revision and set of corrections (mainly grammar) were somehow not included by editing.

2005 January
Licensing Risks, Not Revolutions

• Figure 1: Standard v. source of values of open and closed
  

The primary role of IT is to mitigate risk to corporate investments in information. Simple labels on software like "open" or "proprietary" do little to classify risk to an organization's data and IP. In this article, I'll examine these labels and suggest some new ways to define software types.

2004 November
Dissecting PC Server Performance

• Figure 1: Traditional multiprocessor PC chipset interconnect
• Figure 2: All components content for the northbridge (MCH) even in Xeon MP
  
• Figure 3: Example of proprietary NUMA Xeon MP solution
  
• Figure 4: Socket-754, 939, 940; Socket-478, 603/604 and LGA-775
  
• Figure 5: AMD's Opteron 800 reference design offers more than 50/10GBps of aggregate system/IO throughput
  
• Figure 6: Cheap Opteron 200 OEM designs omit traces and HyperTransport tunnels/bridges
  
• Figure 7: OEM Opteron 200 design with nVidia CK8"Pro" PCI-Express chipset with AMD8131 dual-PCI-X HyperTransport tunnel
  
• Table 1: Processor comparison using Aggregate Front Side Throughput (AFST)
  

Servers are all about I/O. Commodity PC servers have rarely offered high-performance I/O, until now. In this article, I'll dissect PC server design and discuss how to evaluate the performance of AMD Opteron solutions.

2004 April
Dissecting ATA RAID Options

• Figure 1: Data writes via software RAID-1 double the amount of data transfer from memory to I/O
• Figure 2: Data writes via software RAID-5 increase latency while inefficiently utilizing CPU, memory and I/O
• Table 1: The four ATA RAID implementations
  
• Table 2: RAID Cost, DTR and Overhead, by RAID level
  

Advanced Technology Attachment (ATA) is a basic, block transfer interface. In recent ATA specifications (e.g., the UltraDMA modes for parallel ATA or newer Serial ATA), this is little more than a copy of a fixed range of data from primary storage (volatile memory) to secondary storage (non-volatile ATA disk), or vice versa, using direct memory access (DMA). There is minimal system processor involvement in the transfer because the ATA controller arbitrates the DMA transfer on the I/O bus (e.g., PCI) and the integrated device electronics (IDE) of the ATA drive to copy data to and from system memory.

2004 February
Securing Intranets With IPcop

An in-depth defense requires both host and network auditing and detection, in addition to basic host and network perimeter security. Because any security can be defeated, it is essential to be alerted when it has been. There is no greater business liability than an intranet that has become unknowingly compromised.

NOTE: The section on the Snort Intrusion Detection System (IDS) was gutted from the published version.

2002 April
CD Backups with Easy File Access

• Listing 1: back2cd.tcsh
  
• Archive (LZ77/PKZip): Source code for 2002 April issue
  
• Sidebar: Compression: lzop vs. gzip or bzip2
  

Smith introduces the "back2cd" script, which maximizes CD capacity while preserving CD's inherit random-access advantage.

NOTE: Also works for DVD, DVD-DL, etc... as it produces a standard ISO9660 Yellow Book (data) track image file (commonly known as the .iso extension).