# lace card

> form of mechanical system disruption

**Wikidata**: [Q6468188](https://www.wikidata.org/wiki/Q6468188)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Lace_card)  
**Source**: https://4ort.xyz/entity/lace-card

## Summary
A lace card is a type of punched card featuring an intricate lace-like pattern of holes designed to disrupt mechanical card readers. It serves as both a practical joke and a denial-of-service attack, causing system failures by interfering with the reading mechanism.

## Key Facts
- It is a subclass of punched card, a paper-based recording medium used for data storage and processing.
- Classified as both a practical joke and a denial-of-service attack in mechanical systems.
- Known aliases include whoopee card, IBM doily, ventilator card, and flyswatter card.
- Has a sitelink count of 4 across supported platforms.
- Wikipedia articles are available in Arabic, English, Spanish, and Korean.
- Associated freebase ID is /m/0l3nj.
- Depicted in an image at [https://commons.wikimedia.org/wiki/Special:FilePath/IBM_lace_card.jpg](https://commons.wikimedia.org/wiki/Special:FilePath/IBM_lace_card.jpg).

## FAQs
### Q: What is the primary function of a lace card?
A: A lace card disrupts mechanical card readers by creating a pattern of holes that jams or misaligns the reading mechanism, causing system failures. It was deliberately engineered for this purpose.

### Q: How is a lace card different from a standard punched card?
A: Unlike standard punched cards that encode data through hole patterns, lace cards feature decorative, non-functional holes resembling lace. Their sole purpose is interference, not data storage or processing.

### Q: What systems are vulnerable to lace card attacks?
A: Mechanical card readers in early data processing systems, particularly those used by IBM equipment, are susceptible. The lace-like hole pattern physically obstructs the reader's sensors or mechanical components.

## Why It Matters
Lace cards highlight a historical vulnerability in early computing systems, demonstrating how minor physical modifications to input media could cause catastrophic failures. They represent an early form of denial-of-service attack, illustrating the fragility of mechanical computing before electronic safeguards emerged. As a practical joke, they showcase cultural ingenuity in exploiting hardware limitations, serving as a case study in system design failures. Their persistence in historical documentation underscores their significance in computing security evolution.

## Notable For
- Unique among punched cards for its non-functional lace-hole pattern designed purely for disruption.
- One of the earliest recorded denial-of-service attacks targeting mechanical computing hardware.
- Distinguished by its multiple whimsical aliases, reflecting its origins as a prank ("whoopee card," "IBM doily").
- Recognized as a subclass of punched cards but categorized under practical jokes rather than data tools.

## Body
### Overview
A lace card is a specialized punched card characterized by an intricate lace-like pattern of holes. It is engineered to disrupt mechanical card readers by causing physical interference with the reading mechanism, leading to system failures.

### Classification
- **Instance Of**: Practical joke, denial-of-service attack.
- **Subclass Of**: Punched card (paper-based recording medium).
- **Relationships**: Parent class is punched card (61 sitelinks).

### Characteristics
- Hole pattern resembles decorative lace, unlike the data-oriented holes in standard punched cards.
- Purpose is exclusively to obstruct or damage mechanical readers, not to encode data.
- Aliases reflect its dual nature as both a tool and a prank: whoopee card, IBM doily, ventilator card, flyswatter card.

### Documentation
- **Wikipedia Presence**: Articles exist in 4 languages: Arabic, English, Spanish, Korean.
- **External Identifiers**: Freebase ID /m/0l3nj.
- **Visual Evidence**: Official image available via Wikimedia Commons.