Patrick Appiah-Kubi

The Design and Implementation of a Bare PC Email Server

This paper presents the architecture, design and implementation of an email server that runs on a bare PC without an operating system or hard-disk. In addition to providing standard services offered by conventional email servers, the bare PC email server incorporates several unique features leveraging the absence of an operating system. For example, it implements novel algorithms for optimal multi-tasking, provides streamlined processing of messages enabling highly efficient integration of the SMTP and POP3 servers, and minimizes traditional software and protocol overhead. Additionally, it eliminates process overhead due to an operating system, offers enhanced security since the server is not vulnerable to attacks that target operating system flaws, and has a smaller code size. The complete server can be booted from removable media such as a USB drive. The bare PC email server demonstrates the ability of a self-contained, self-executing, complex software application to directly control the underlying PC hardware.

The Performance of a Bare Machine Email Server

Bare machine applications run directly over the hardware without using an operating system or a hard disk. This paper studies the performance of a bare machine email server whose design and implementation is based on several novel architectural features with a view towards optimizing performance. The results are compared with those for the AxiGen and ShareMailPro email servers, and a lean Java-based email server prototype running on Windows whose application-level operation closely matches that of the bare machine email server. For 80,000 emails in a LAN environment, the bare Machine server processing time is approximately 2 times faster than a Java-based server, and 2.4 times faster than the AxiGen server. For 5,500 emails in a WAN environment, the bare machine server performed at least 1.8 times faster than the Java-based and ShareMailPro servers. The results indicate that the bare machine email server outperforms the conventional email servers in LAN and WAN environments, and demonstrate the capability of using bare machines to build high-performance email servers.

Design and Performance of a Webmail Server on Bare PC

We describe a Webmail server that runs on a bare PC without an operating system (OS) or kernel, and give details of its architecture, design, and implementation. We also present the results of experiments conducted in a test LAN environment to compare performance of the bare PC Webmail server with conventional Webmail servers Atmail and Mailtraq running on Linux and Windows respectively. Performance is evaluated by measuring the processing time for login requests; inbox requests with a varying number of emails; and composing or retrieving email messages and sending attachments of various sizes. We also measure the throughput for various sizes; and, under stress conditions, the processing and response times with a varying number of connections, and the total and average processing times for the POST command with a varying number of users. The results show that the performance of the bare PC Webmail server is significantly better than that of the OS-based servers. The bare PC Webmail server is an alternative to conventional Webmail systems, and its architecture and design features could be used as a basis for developing future high-performance systems.

A Methodology to Transform an OS-Based Application to a Bare Machine Application

This paper describes a novel approach to transform application programs that run with the support of an operating system or kernel to bare machine applications that run with no intermediary software of any kind in the machine. The general transformation methodology is based on a simple model that views application software as code with system header files and calls. These files and underlying system calls are removed in order to transform the application without understanding details of the application or its internal behavior. A Windows SQLite database engine application is chosen to illustrate the transformation process, and the transformed application is run on a bare PC to demonstrate the feasibility of this approach. The Microsoft Windows Visual Studio environment (IDE) is used to facilitate the transformation process. Sample database queries are run on a bare PC, and also in Visual Studio, and the results are validated by comparison. Currently, the application code is transformed manually, however, the experiences and skills acquired could be leveraged to develop an automated tool in the future. This methodology and transformation model serves as a basis for converting a variety of applications and other software to run on bare machines by achieving automatic ubiquity without a need for a virtual machine. When the general transformation methodology is fully tested, made robust, and automated, existing computer software can be transformed with little effort to make them independent of any operating environment.

An experimental evaluation of IP4-IPV6 IVI translation

While IPv6 deployment in the Internet continues to grow slowly at present, the imminent exhaustion of IPv4 addresses will encourage its increased use over the next several years. However, due to the predominance of IPv4 in the Internet, the transition to IPv6 is likely to take a long time. During the transition period, translation mechanisms will enable IPv6 hosts and IPv4 hosts to communicate with each other. For example, translation can be used when a server or application works with IPv4 but not with IPv6, and the effort or cost to modify the code is large. Stateless and stateful translation is the subject of several recent IETF RFCs. We evaluate performance of the new IVI translator, which is viewed as a design for stateless translation by conducting experiments in both LAN and Internet environments using a freely available Linux implementation of IVI. To study the impact of operating system overhead on IVI translation, we implemented the IVI translator on a bare PC that runs applications without an operating system or kernel. Our results based on internal timings in each system show that translating IPv4 packets into IPv6 packets is more expensive than the reverse, and that address mapping is the most expensive IVI operation. We also measured packets per second in the LAN, roundtrip times in the LAN and Internet, IVI overhead for various prefix sizes, TCP connection time, and the delay and throughput over the Internet for various files sizes. While both the Linux and bare PC implementations of IVI have low overhead, a modest performance gain is obtained due to using a bare PC.

A bare PC TLS Webmail Server

Bare PC systems have no operating system or kernel, and can be used for building self-supporting server applications that perform better than conventional servers. The bare PC server application contains the necessary network protocols, does its own memory allocation and task scheduling, and uses direct interfaces to the hardware. We discuss the design and implementation of a TLS Webmail server that runs on a bare PC. Novel design features of the server include intertwining the TLS, HTTP and TCP protocols to reduce inter-layer communication overhead, and using a separate TLS task per connection to improve performance. We also present initial performance measurements in a LAN environment to measure the overhead due to TLS, and the possible speed-up that can be achieved compared to conventional TLS Webmail servers. The results suggest that customized bare PC servers could be designed in the future to meet the security and performance requirements of pervasive computing environments.

Transforming a bare PC application to run on an ARM device

Bare machine applications currently run on x86-based CPUs without any operating system or kernel support. Their low overhead makes them especially suited for mobile devices and pervasive computing. As an initial step towards running bare applications on mobile devices, we transform an x86-based bare PC graphics application to run on an ARM device. We first identify key differences between the x86 and ARM architectures relevant to the transformation. We then describe a methodology to transform the x86-based bare graphics application to run on the ARM architecture. We also present timing measurements when drawing graphics functions using the same bare application on an x86 bare PC, ARM development board, DOSBox emulator, and QEMU-VM simulator. This work provides insight into designing future bare machine applications that can run on a variety of mobile and pervasive devices with minimal code changes.