050-100 Open Source Essentials Practice Questions
Prepare for 050-100 with more than an answer.
- 1
A hardware manufacturer embeds Linux-based firmware into a consumer smart television. The device uses software licensed under GNU General Public License version 2 (GPLv2). Although the vendor provides the full source code for the firmware, the hardware uses cryptographic signature verification in ROM that refuses to boot any modified firmware image created by the user. Which concept specifically describes this scenario, and which open source license was designed specifically to prevent it?
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Correct answer: C
'Tivoization' (named after the TiVo digital video recorder) describes the practice of distributing hardware containing copyleft open source software alongside its source code, but utilizing hardware restrictions (such as signature-locked bootloaders) to prevent users from executing their own modified versions on that physical device. The Free Software Foundation drafted GPLv3 specifically to prohibit this practice by obligating distributors of 'User Products' to supply the necessary Installation Information (cryptographic keys/signatures) to install and run modified software.
flowchart TD A[Device Powered On] --> B[Hardware Bootloader] B --> C{Vendor Cryptographic Signature Valid?} C -- Yes --> D[Run Firmware Binary] C -- No --> E[Refuse Execution: Tivoization] - 2
A financial analytics company creates a hosted cloud service. The backend server modifies and executes an open source algorithmic engine without ever distributing binary or source code artifacts directly to external customers. End users only interact with the service over HTTPS by submitting financial data queries. Which copyleft license imposes a strict legal obligation on the company to make the engine's complete modified source code accessible to all remote users interacting with it over the computer network?
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Correct answer: A
Under standard copyleft licenses like GPLv2 and GPLv3, copyleft triggers only upon 'distribution' or 'conveyance' of binary software to third parties. Hosting an application on a server as Software as a Service (SaaS) does not constitute traditional distribution, creating what was known as the 'Application Service Provider (ASP) loophole'. The GNU Affero General Public License version 3 (AGPLv3) closes this loophole via Section 13: if a modified version interacts with users remotely through a computer network, the host must prominently offer all users access to the Corresponding Source of the modified version over that network without charge.
- 3
A medical device company builds a proprietary diagnostic monitor application. The software architecture links against a mathematical calculations library distributed under the GNU Lesser General Public License version 2.1 (LGPLv2.1).
The legal department must ensure that the proprietary application code remains closed source and protected under corporate copyright, while strictly satisfying the LGPLv2.1 compliance obligations when shipping the physical diagnostic hardware.
Which engineering approach satisfies LGPLv2.1 obligations without forcing the company to release the source code of its proprietary application?
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Correct answer: D
LGPLv2.1 Section 6 is designed to permit linking proprietary programs with LGPL libraries provided users have the practical freedom to modify the LGPL library and relink their application against the modified library. This is typically accomplished by dynamically linking against a shared library (.so or .dll) and providing the source code of the LGPL library (with any modifications). Alternatively, if statically linked, the distributor must provide the unlinked object code (.o) of the proprietary application so the user can re-link with an updated library version.
- 4
A developer integrates source code files licensed under the Mozilla Public License 2.0 (MPL 2.0) into a broader enterprise software project alongside custom, proprietary source code files. Which statement accurately reflects the 'weak copyleft' boundaries enforced by MPL 2.0?
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Correct answer: A
The Mozilla Public License 2.0 (MPL 2.0) is a classic 'weak copyleft' (or file-level copyleft) license. Under MPL 2.0, if an engineer edits or modifies an existing file covered by MPL 2.0, that file must be made available under MPL 2.0 upon distribution. However, if new code is placed into separate files, even within a larger composite program combining MPL and non-MPL files, those separate files are not infected by copyleft and may remain proprietary.
- 5
A systems architect is evaluating compilation and linking strategies for a constrained Linux-based Internet of Things (IoT) edge device with limited Flash storage and strict operational memory constraints. The system runs ten separate daemon processes that all rely on a custom cryptography utility library. Which linking strategy provides the most efficient utilization of physical system memory (RAM) across these concurrent processes, and why?
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Correct answer: A
Dynamic linking relies on shared libraries (.so files on Linux) where the operating system loader maps the read-only text (code) segment of the library into physical memory only once, sharing pages across multiple independent process virtual address spaces. In contrast, static linking copies the entire library code into each executable binary, duplicating that memory footprint across each running daemon process. While static linking avoids runtime library missing dependencies, it wastes significant RAM and Flash storage when multiple running programs use the same library.
- 6
During the software build and deployment phase of a multi-language software stack, an engineer distinguishes between native binaries, interpreted scripts, and bytecode-compiled software. Which execution model describes how Java and Python source code is processed before execution on a host system?
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Correct answer: C
Both Java and Python compile human-readable source code into an intermediate, architecture-neutral representation called bytecode (.class files in Java, .pyc files in Python). This bytecode is then executed inside a runtime virtual machine (such as the JVM or CPython VM), which translates the bytecode into CPU-specific machine instructions on the fly or via Just-In-Time (JIT) compilation. This contrasts with purely native ahead-of-time compilation (like C/C++ or Rust) and pure direct interpretation.
